248 (two hundred ndforty-eight) is the

natural number In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive in ...

following 247 and preceding

249 __NOTOC__ Year 249 ( CCXLIX) was a common year starting on Monday of the Julian calendar. At the time, it was known as the Year of the Consulship of Gavius and Aquilinus (or, less frequently, year 1002 ''Ab urbe condita''). The denomination 24 ...

. Additionally, 248 is: *a

nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotie ...

. *a refactorable number. *an

untouchable number In mathematics, an untouchable number is a positive integer that cannot be expressed as the sum of all the proper divisors of any positive integer. That is, these numbers are not in the image of the aliquot sum function. Their study goes back at l ...

. *palindromic in bases 13 (161₁₃), 30 (88₃₀), 61 (44₆₁) and 123 (22₁₂₃). *a

Harshad number In mathematics, a harshad number (or Niven number) in a given radix, number base is an integer that is divisible by the digit sum, sum of its digits when written in that base. Harshad numbers in base are also known as -harshad (or -Niven) numbers ...

in bases 3, 4, 6, 7, 9, 11, 13 (and 18 other bases). *part of the 43-aliquot tree. The aliquot sequence starting at 248 is: 248, 232, 218, 112, 136, 134, 70, 74, 40, 50, 43, 1, 0. The exceptional

Lie group In mathematics, a Lie group (pronounced ) is a group (mathematics), group that is also a differentiable manifold, such that group multiplication and taking inverses are both differentiable. A manifold is a space that locally resembles Eucli ...

E₈ has dimension 248.

References

Integers {{Num-stub