638442459768960 has 2560 divisors, whose sum is σ = 2877729061109760. Its totient is φ = 131029954560000.

The previous prime is 638442459768931. The next prime is 638442459768973. The reversal of 638442459768960 is 69867954244836.

638442459768960 is a `hidden beast` number, since 6 + 3 + 8 + 4 + 4 + 2 + 459 + 76 + 8 + 96 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a self number, because there is not a number n which added to its sum of digits gives 638442459768960.

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 188275568865 + ... + 188275572255.

It is an arithmetic number, because the mean of its divisors is an integer number (1124112914496).

Almost surely, 2^{638442459768960} is an apocalyptic number.

638442459768960 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638442459768960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1438864530554880).

638442459768960 is an abundant number, since it is smaller than the sum of its proper divisors (2239286601340800).

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

638442459768960 is a wasteful number, since it uses less digits than its factorization.

638442459768960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4008 (or 3987 counting only the distinct ones).

The product of its (nonzero) digits is 15049359360, while the sum is 81.

The spelling of 638442459768960 in words is "six hundred thirty-eight trillion, four hundred forty-two billion, four hundred fifty-nine million, seven hundred sixty-eight thousand, nine hundred sixty".