640605385 has 16 divisors (see below), whose sum is σ = 884448000. Its totient is φ = 436320576.

The previous prime is 640605377. The next prime is 640605409. The reversal of 640605385 is 583506046.

It is a cyclic number.

It is not a de Polignac number, because 640605385 - 2³ = 640605377 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56205 + ... + 66634.

It is an arithmetic number, because the mean of its divisors is an integer number (55278000).

Almost surely, 2^640605385 is an apocalyptic number.

It is an amenable number.

640605385 is a deficient number, since it is larger than the sum of its proper divisors (243842615).

640605385 is a wasteful number, since it uses less digits than its factorization.

640605385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123000.

The product of its (nonzero) digits is 86400, while the sum is 37.

The square root of 640605385 is about 25310.1834248589. The cubic root of 640605385 is about 862.0455117254.

The spelling of 640605385 in words is "six hundred forty million, six hundred five thousand, three hundred eighty-five".