640688575 has 12 divisors (see below), whose sum is σ = 828996048. Its totient is φ = 490265600.

The previous prime is 640688567. The next prime is 640688579. The reversal of 640688575 is 575886046.

It is not a de Polignac number, because 640688575 - 2³ = 640688567 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640688579) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 556546 + ... + 557695.

It is an arithmetic number, because the mean of its divisors is an integer number (69083004).

Almost surely, 2^640688575 is an apocalyptic number.

640688575 is a deficient number, since it is larger than the sum of its proper divisors (188307473).

640688575 is a wasteful number, since it uses less digits than its factorization.

640688575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1114274 (or 1114269 counting only the distinct ones).

The product of its (nonzero) digits is 1612800, while the sum is 49.

The square root of 640688575 is about 25311.8267811709. The cubic root of 640688575 is about 862.0828256287.

The spelling of 640688575 in words is "six hundred forty million, six hundred eighty-eight thousand, five hundred seventy-five".