638844663120 has 80 divisors (see below), whose sum is σ = 1981177154880. Its totient is φ = 170293312512.

The previous prime is 638844663103. The next prime is 638844663167. The reversal of 638844663120 is 21366448836.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 119511 + ... + 1136649.

It is an arithmetic number, because the mean of its divisors is an integer number (24764714436).

Almost surely, 2^638844663120 is an apocalyptic number.

638844663120 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

638844663120 is an abundant number, since it is smaller than the sum of its proper divisors (1342332491760).

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

638844663120 is a wasteful number, since it uses less digits than its factorization.

638844663120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1019772 (or 1019766 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 51.

The spelling of 638844663120 in words is "six hundred thirty-eight billion, eight hundred forty-four million, six hundred sixty-three thousand, one hundred twenty".