21791765642400 has 1152 divisors, whose sum is σ = 89962967001600. Its totient is φ = 5043304857600.

The previous prime is 21791765642389. The next prime is 21791765642411. The reversal of 21791765642400 is 424656719712.

21791765642400 is a `hidden beast` number, since 2 + 1 + 7 + 9 + 1 + 76 + 564 + 2 + 4 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21791765642389) and next prime (21791765642411).

It is a super-5 number, since 5×21791765642400⁵ (a number of 68 digits) contains 55555 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 6296376670 + ... + 6296380130.

It is an arithmetic number, because the mean of its divisors is an integer number (78092853300).

Almost surely, 2^{21791765642400} is an apocalyptic number.

21791765642400 is a gapful number since it is divisible by the number (20) 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 21791765642400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44981483500800).

21791765642400 is an abundant number, since it is smaller than the sum of its proper divisors (68171201359200).

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

21791765642400 is a wasteful number, since it uses less digits than its factorization.

21791765642400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4839 (or 4820 counting only the distinct ones).

The product of its (nonzero) digits is 5080320, while the sum is 54.

The spelling of 21791765642400 in words is "twenty-one trillion, seven hundred ninety-one billion, seven hundred sixty-five million, six hundred forty-two thousand, four hundred".