253 (number)

253 (two hundred [and] fifty-three) is the natural number following 252 and preceding 254.

In mathematics
253 is: $$10^{506}-10^{253}-1$$ is a prime number. Its decimal expansion is 252 nines, an eight, and 253 more nines.
 * a semiprime since it is the product of 2 primes.
 * a triangular number.
 * a star number.
 * a centered heptagonal number.
 * a centered nonagonal number.
 * a Blum integer.
 * a member of the 13-aliquot tree.