251663664 has 160 divisors (see below), whose sum is σ = 793600000. Its totient is φ = 67122432.

The previous prime is 251663567. The next prime is 251663681. The reversal of 251663664 is 466366152.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 504087 + ... + 504585.

It is an arithmetic number, because the mean of its divisors is an integer number (4960000).

Almost surely, 2^251663664 is an apocalyptic number.

251663664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251663664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (396800000).

251663664 is an abundant number, since it is smaller than the sum of its proper divisors (541936336).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

251663664 is a wasteful number, since it uses less digits than its factorization.

251663664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 615 (or 609 counting only the distinct ones).

The product of its digits is 155520, while the sum is 39.

The square root of 251663664 is about 15863.9107410500. The cubic root of 251663664 is about 631.3548268353.

The spelling of 251663664 in words is "two hundred fifty-one million, six hundred sixty-three thousand, six hundred sixty-four".