21620129581296 has 540 divisors, whose sum is σ = 64584040778712. Its totient is φ = 7010653358592.

The previous prime is 21620129581283. The next prime is 21620129581313. The reversal of 21620129581296 is 69218592102612.

21620129581296 is a `hidden beast` number, since 2 + 1 + 6 + 20 + 12 + 9 + 581 + 29 + 6 = 666.

It is a super-2 number, since 2×21620129581296² (a number of 27 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 46295780455 + ... + 46295780921.

Almost surely, 2^{21620129581296} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21620129581296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32292020389356).

21620129581296 is an abundant number, since it is smaller than the sum of its proper divisors (42963911197416).

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

21620129581296 is an frugal number, since it uses more digits than its factorization.

21620129581296 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 762 (or 682 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 54.

The spelling of 21620129581296 in words is "twenty-one trillion, six hundred twenty billion, one hundred twenty-nine million, five hundred eighty-one thousand, two hundred ninety-six".