640526625 has 72 divisors (see below), whose sum is σ = 1197611064. Its totient is φ = 329347200.

The previous prime is 640526617. The next prime is 640526693. The reversal of 640526625 is 526625046.

640526625 is a `hidden beast` number, since 6 + 4 + 0 + 5 + 26 + 625 = 666.

It can be written as a sum of positive squares in 12 ways, for example, as 216001809 + 424524816 = 14697^2 + 20604^2 .

It is not a de Polignac number, because 640526625 - 2³ = 640526617 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640526625.

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 71 ways as a sum of consecutive naturals, for example, 945787 + ... + 946463.

It is an arithmetic number, because the mean of its divisors is an integer number (16633487).

Almost surely, 2^640526625 is an apocalyptic number.

It is an amenable number.

640526625 is a deficient number, since it is larger than the sum of its proper divisors (557084439).

640526625 is a wasteful number, since it uses less digits than its factorization.

640526625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 756 (or 714 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 640526625 is about 25308.6274815526. The cubic root of 640526625 is about 862.0101818699.

The spelling of 640526625 in words is "six hundred forty million, five hundred twenty-six thousand, six hundred twenty-five".