640571540 has 48 divisors (see below), whose sum is σ = 1541068032. Its totient is φ = 219096576.

The previous prime is 640571521. The next prime is 640571549. The reversal of 640571540 is 45175046.

640571540 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 640571497 and 640571506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640571549) by changing a digit.

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, 55337 + ... + 65903.

It is an arithmetic number, because the mean of its divisors is an integer number (32105584).

Almost surely, 2^640571540 is an apocalyptic number.

It is an amenable number.

640571540 is an abundant number, since it is smaller than the sum of its proper divisors (900496492).

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

640571540 is a wasteful number, since it uses less digits than its factorization.

640571540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11016 (or 11014 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 32.

The square root of 640571540 is about 25309.5148116277. The cubic root of 640571540 is about 862.0303300213.

The spelling of 640571540 in words is "six hundred forty million, five hundred seventy-one thousand, five hundred forty".