251961664 has 28 divisors (see below), whose sum is σ = 501091200. Its totient is φ = 125702528.

The previous prime is 251961649. The next prime is 251961673. The reversal of 251961664 is 466169152.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26547 + ... + 34765.

Almost surely, 2^251961664 is an apocalyptic number.

It is an amenable number.

251961664 is a deficient number, since it is larger than the sum of its proper divisors (249129536).

251961664 is an equidigital number, since it uses as much as digits as its factorization.

251961664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8710 (or 8700 counting only the distinct ones).

The product of its digits is 77760, while the sum is 40.

The square root of 251961664 is about 15873.3003499587. The cubic root of 251961664 is about 631.6039285168.

The spelling of 251961664 in words is "two hundred fifty-one million, nine hundred sixty-one thousand, six hundred sixty-four".