251140865 has 16 divisors (see below), whose sum is σ = 305084880. Its totient is φ = 198451200.

The previous prime is 251140859. The next prime is 251140913. The reversal of 251140865 is 568041152.

It can be written as a sum of positive squares in 8 ways, for example, as 80263681 + 170877184 = 8959^2 + 13072^2 .

It is not a de Polignac number, because 251140865 - 2⁶ = 251140801 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 156065 + ... + 157665.

It is an arithmetic number, because the mean of its divisors is an integer number (19067805).

Almost surely, 2^251140865 is an apocalyptic number.

It is an amenable number.

251140865 is a deficient number, since it is larger than the sum of its proper divisors (53944015).

251140865 is a wasteful number, since it uses less digits than its factorization.

251140865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1972.

The product of its (nonzero) digits is 9600, while the sum is 32.

The square root of 251140865 is about 15847.4245541665. The cubic root of 251140865 is about 630.9173375138.

The spelling of 251140865 in words is "two hundred fifty-one million, one hundred forty thousand, eight hundred sixty-five".