251132640 has 96 divisors (see below), whose sum is σ = 863001216. Its totient is φ = 60879360.

The previous prime is 251132593. The next prime is 251132641. The reversal of 251132640 is 46231152.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 251132640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251132641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18502 + ... + 29061.

It is an arithmetic number, because the mean of its divisors is an integer number (8989596).

Almost surely, 2^251132640 is an apocalyptic number.

251132640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251132640 is an abundant number, since it is smaller than the sum of its proper divisors (611868576).

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

251132640 is a wasteful number, since it uses less digits than its factorization.

251132640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47592 (or 47584 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 251132640 is about 15847.1650461526. The cubic root of 251132640 is about 630.9104498099.

Adding to 251132640 its reverse (46231152), we get a palindrome (297363792).

The spelling of 251132640 in words is "two hundred fifty-one million, one hundred thirty-two thousand, six hundred forty".