639645837954816 has 432 divisors, whose sum is σ = 2264336976690432. Its totient is φ = 156368727736320.

The previous prime is 639645837954779. The next prime is 639645837954853. The reversal of 639645837954816 is 618459738546936.

It is an interprime number because it is at equal distance from previous prime (639645837954779) and next prime (639645837954853).

It is a Harshad number since it is a multiple of its sum of digits (84).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 17862750 + ... + 39979613.

It is an arithmetic number, because the mean of its divisors is an integer number (5241520779376).

Almost surely, 2^{639645837954816} is an apocalyptic number.

639645837954816 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

639645837954816 is an abundant number, since it is smaller than the sum of its proper divisors (1624691138735616).

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

639645837954816 is a wasteful number, since it uses less digits than its factorization.

639645837954816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57842428 (or 57842403 counting only the distinct ones).

The product of its digits is 28217548800, while the sum is 84.

The spelling of 639645837954816 in words is "six hundred thirty-nine trillion, six hundred forty-five billion, eight hundred thirty-seven million, nine hundred fifty-four thousand, eight hundred sixteen".