251075664 has 120 divisors (see below), whose sum is σ = 812989632. Its totient is φ = 70848000.

The previous prime is 251075663. The next prime is 251075683. The reversal of 251075664 is 466570152.

It is a happy number.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251075663) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 82164 + ... + 85164.

Almost surely, 2^251075664 is an apocalyptic number.

251075664 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 251075664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (406494816).

251075664 is an abundant number, since it is smaller than the sum of its proper divisors (561913968).

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

251075664 is a wasteful number, since it uses less digits than its factorization.

251075664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3105 (or 3096 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The square root of 251075664 is about 15845.3672724869. The cubic root of 251075664 is about 630.8627333620.

The spelling of 251075664 in words is "two hundred fifty-one million, seventy-five thousand, six hundred sixty-four".