640604987 has 16 divisors (see below), whose sum is σ = 725621760. Its totient is φ = 560272800.

The previous prime is 640604977. The next prime is 640604989. The reversal of 640604987 is 789406046.

It is a cyclic number.

It is not a de Polignac number, because 640604987 - 2¹⁰ = 640603963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640604989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53564 + ... + 64422.

It is an arithmetic number, because the mean of its divisors is an integer number (45351360).

Almost surely, 2^640604987 is an apocalyptic number.

640604987 is a deficient number, since it is larger than the sum of its proper divisors (85016773).

640604987 is a wasteful number, since it uses less digits than its factorization.

640604987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11074.

The product of its (nonzero) digits is 290304, while the sum is 44.

The square root of 640604987 is about 25310.1755624097. The cubic root of 640604987 is about 862.0453331994.

The spelling of 640604987 in words is "six hundred forty million, six hundred four thousand, nine hundred eighty-seven".