12638665544400 has 720 divisors, whose sum is σ = 50366738822400. Its totient is φ = 2874964377600.

The previous prime is 12638665544387. The next prime is 12638665544419. The reversal of 12638665544400 is 444556683621.

12638665544400 is a `hidden beast` number, since 1 + 2 + 6 + 3 + 86 + 6 + 554 + 4 + 4 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 5216121589 + ... + 5216124011.

It is an arithmetic number, because the mean of its divisors is an integer number (69953803920).

Almost surely, 2^{12638665544400} is an apocalyptic number.

12638665544400 is a gapful number since it is divisible by the number (10) 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 12638665544400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25183369411200).

12638665544400 is an abundant number, since it is smaller than the sum of its proper divisors (37728073278000).

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

12638665544400 is a wasteful number, since it uses less digits than its factorization.

12638665544400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3364 (or 3350 counting only the distinct ones).

The product of its (nonzero) digits is 16588800, while the sum is 54.

The spelling of 12638665544400 in words is "twelve trillion, six hundred thirty-eight billion, six hundred sixty-five million, five hundred forty-four thousand, four hundred".