639905812042 has 16 divisors (see below), whose sum is σ = 1097026032960. Its totient is φ = 274234187808.

The previous prime is 639905812031. The next prime is 639905812079. The reversal of 639905812042 is 240218509936.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 568867 + ... + 1266262.

It is an arithmetic number, because the mean of its divisors is an integer number (68564127060).

Almost surely, 2^639905812042 is an apocalyptic number.

639905812042 is a deficient number, since it is larger than the sum of its proper divisors (457120220918).

639905812042 is a wasteful number, since it uses less digits than its factorization.

639905812042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1860045.

The product of its (nonzero) digits is 933120, while the sum is 49.

The spelling of 639905812042 in words is "six hundred thirty-nine billion, nine hundred five million, eight hundred twelve thousand, forty-two".