21520255633724 has 6 divisors (see below), whose sum is σ = 37660447359024. Its totient is φ = 10760127816860.

The previous prime is 21520255633687. The next prime is 21520255633739. The reversal of 21520255633724 is 42733655202512.

It is a super-2 number, since 2×21520255633724² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2690031954212 + ... + 2690031954219.

It is an arithmetic number, because the mean of its divisors is an integer number (6276741226504).

Almost surely, 2^{21520255633724} is an apocalyptic number.

It is an amenable number.

21520255633724 is a deficient number, since it is larger than the sum of its proper divisors (16140191725300).

21520255633724 is a wasteful number, since it uses less digits than its factorization.

21520255633724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5380063908435 (or 5380063908433 counting only the distinct ones).

The product of its (nonzero) digits is 3024000, while the sum is 47.

The spelling of 21520255633724 in words is "twenty-one trillion, five hundred twenty billion, two hundred fifty-five million, six hundred thirty-three thousand, seven hundred twenty-four".