640604986 has 16 divisors (see below), whose sum is σ = 1104759936. Its totient is φ = 272900016.

The previous prime is 640604977. The next prime is 640604989. The reversal of 640604986 is 689406046.

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

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 134661 + ... + 139336.

It is an arithmetic number, because the mean of its divisors is an integer number (69047496).

Almost surely, 2^640604986 is an apocalyptic number.

640604986 is a deficient number, since it is larger than the sum of its proper divisors (464154950).

640604986 is a wasteful number, since it uses less digits than its factorization.

640604986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274173.

The product of its (nonzero) digits is 248832, while the sum is 43.

The square root of 640604986 is about 25310.1755426548. The cubic root of 640604986 is about 862.0453327508.

The spelling of 640604986 in words is "six hundred forty million, six hundred four thousand, nine hundred eighty-six".