253 (two hundred [and] fifty-three) is the natural number following 252 and preceding 254.
In mathematics 253 is:
a semiprime since it is the product of 2 primes. a brilliant number, meaning that its prime factors have the same amount of digits the 22nd triangular number. a star number. a centered heptagonal number. a centered nonagonal number. a Blum integer. a member of the 13-aliquot tree.
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