251486865 has 72 divisors (see below), whose sum is σ = 536987880. Its totient is φ = 108186624.

The previous prime is 251486843. The next prime is 251486867. The reversal of 251486865 is 568684152.

It can be written as a sum of positive squares in 4 ways, for example, as 69155856 + 182331009 = 8316^2 + 13503^2 .

It is not a de Polignac number, because 251486865 - 2⁷ = 251486737 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 251486865.

It is not an unprimeable number, because it can be changed into a prime (251486867) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 34131 + ... + 40839.

It is an arithmetic number, because the mean of its divisors is an integer number (7458165).

Almost surely, 2^251486865 is an apocalyptic number.

It is an amenable number.

251486865 is an abundant number, since it is smaller than the sum of its proper divisors (285501015).

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

251486865 is a wasteful number, since it uses less digits than its factorization.

251486865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6751 (or 6741 counting only the distinct ones).

The product of its digits is 460800, while the sum is 45.

The square root of 251486865 is about 15858.3373970918. The cubic root of 251486865 is about 631.2069455326.

The spelling of 251486865 in words is "two hundred fifty-one million, four hundred eighty-six thousand, eight hundred sixty-five".