639798587866 has 16 divisors (see below), whose sum is σ = 967085241408. Its totient is φ = 317437151200.

The previous prime is 639798587849. The next prime is 639798587903. The reversal of 639798587866 is 668785897936.

It is a self number, because there is not a number n which added to its sum of digits gives 639798587866.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4590486 + ... + 4727806.

It is an arithmetic number, because the mean of its divisors is an integer number (60442827588).

Almost surely, 2^639798587866 is an apocalyptic number.

639798587866 is a deficient number, since it is larger than the sum of its proper divisors (327286653542).

639798587866 is a wasteful number, since it uses less digits than its factorization.

639798587866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155237.

The product of its digits is 6584094720, while the sum is 82.

It can be divided in two parts, 639798 and 587866, that added together give a square (1227664 = 1108²).

The spelling of 639798587866 in words is "six hundred thirty-nine billion, seven hundred ninety-eight million, five hundred eighty-seven thousand, eight hundred sixty-six".