639959946 has 16 divisors (see below), whose sum is σ = 1288074144. Its totient is φ = 211960944.

The previous prime is 639959941. The next prime is 639959953. The reversal of 639959946 is 649959936.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 639959946.

It is not an unprimeable number, because it can be changed into a prime (639959941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 338740 + ... + 340623.

It is an arithmetic number, because the mean of its divisors is an integer number (80504634).

Almost surely, 2^639959946 is an apocalyptic number.

639959946 is an abundant number, since it is smaller than the sum of its proper divisors (648114198).

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

639959946 is a wasteful number, since it uses less digits than its factorization.

639959946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 679525.

The product of its digits is 14171760, while the sum is 60.

The square root of 639959946 is about 25297.4296322769. The cubic root of 639959946 is about 861.7558977779.

The spelling of 639959946 in words is "six hundred thirty-nine million, nine hundred fifty-nine thousand, nine hundred forty-six".