639128813466 has 32 divisors (see below), whose sum is σ = 1501729242048. Its totient is φ = 178777290240.

The previous prime is 639128813443. The next prime is 639128813473. The reversal of 639128813466 is 664318821936.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 15 ways as a sum of consecutive naturals, for example, 372451831 + ... + 372453546.

It is an arithmetic number, because the mean of its divisors is an integer number (46929038814).

Almost surely, 2^639128813466 is an apocalyptic number.

639128813466 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

639128813466 is an abundant number, since it is smaller than the sum of its proper divisors (862600428582).

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

639128813466 is a wasteful number, since it uses less digits than its factorization.

639128813466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 744905406.

The product of its digits is 8957952, while the sum is 57.

The spelling of 639128813466 in words is "six hundred thirty-nine billion, one hundred twenty-eight million, eight hundred thirteen thousand, four hundred sixty-six".