21620379651984 has 405 divisors, whose sum is σ = 67259606372049. Its totient is φ = 6481410186240.

The previous prime is 21620379651931. The next prime is 21620379652037. The reversal of 21620379651984 is 48915697302612.

The square root of 21620379651984 is 4649772.

It is a perfect power (a square), and thus also a powerful number.

21620379651984 is a `hidden beast` number, since 2 + 1 + 6 + 2 + 0 + 37 + 9 + 6 + 519 + 84 = 666.

It is an interprime number because it is at equal distance from previous prime (21620379651931) and next prime (21620379652037).

It can be written as a sum of positive squares in only one way, i.e., 16832475507600 + 4787904144384 = 4102740^2 + 2188128^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 21816729729 + ... + 21816730719.

It is a 1-persistent number, because it is pandigital, but 2⋅21620379651984 = 43240759303968 is not.

Almost surely, 2^{21620379651984} is an apocalyptic number.

21620379651984 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

21620379651984 is the 4649772-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21620379651984

21620379651984 is an abundant number, since it is smaller than the sum of its proper divisors (45639226720065).

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

21620379651984 is an equidigital number, since it uses as much as digits as its factorization.

21620379651984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2076 (or 1036 counting only the distinct ones).

The product of its (nonzero) digits is 39191040, while the sum is 63.

The spelling of 21620379651984 in words is "twenty-one trillion, six hundred twenty billion, three hundred seventy-nine million, six hundred fifty-one thousand, nine hundred eighty-four".