640635542 has 16 divisors (see below), whose sum is σ = 979290000. Its totient is φ = 314233440.

The previous prime is 640635487. The next prime is 640635551. The reversal of 640635542 is 245536046.

It is a happy number.

640635542 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40709 + ... + 54207.

It is an arithmetic number, because the mean of its divisors is an integer number (61205625).

Almost surely, 2^640635542 is an apocalyptic number.

640635542 is a deficient number, since it is larger than the sum of its proper divisors (338654458).

640635542 is a wasteful number, since it uses less digits than its factorization.

640635542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13951.

The product of its (nonzero) digits is 86400, while the sum is 35.

The square root of 640635542 is about 25310.7791661972. The cubic root of 640635542 is about 862.0590386689.

The spelling of 640635542 in words is "six hundred forty million, six hundred thirty-five thousand, five hundred forty-two".