640541625 has 32 divisors (see below), whose sum is σ = 1070659200. Its totient is φ = 340084800.

The previous prime is 640541621. The next prime is 640541677. The reversal of 640541625 is 526145046.

640541625 = T₄₅₄ + T₄₅₅ + ... + T₁₅₇₈.

It is not a de Polignac number, because 640541625 - 2² = 640541621 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640541621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 82146 + ... + 89604.

It is an arithmetic number, because the mean of its divisors is an integer number (33458100).

Almost surely, 2^640541625 is an apocalyptic number.

It is an amenable number.

640541625 is a deficient number, since it is larger than the sum of its proper divisors (430117575).

640541625 is a wasteful number, since it uses less digits than its factorization.

640541625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7706 (or 7696 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

The square root of 640541625 is about 25308.9238214508. The cubic root of 640541625 is about 862.0169107350.

The spelling of 640541625 in words is "six hundred forty million, five hundred forty-one thousand, six hundred twenty-five".