21356530938873 has 24 divisors (see below), whose sum is σ = 33848086780872. Its totient is φ = 12894509242368.

The previous prime is 21356530938857. The next prime is 21356530938937. The reversal of 21356530938873 is 37883903565312.

21356530938873 is a `hidden beast` number, since 2 + 1 + 3 + 5 + 6 + 530 + 93 + 8 + 8 + 7 + 3 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1140105011049 + 20216425927824 = 1067757^2 + 4496268^2 .

It is not a de Polignac number, because 21356530938873 - 2⁴ = 21356530938857 is a prime.

It is a super-2 number, since 2×21356530938873² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21356530938873.

It is not an unprimeable number, because it can be changed into a prime (21356530938473) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1722016936 + ... + 1722029337.

It is an arithmetic number, because the mean of its divisors is an integer number (1410336949203).

Almost surely, 2^{21356530938873} is an apocalyptic number.

It is an amenable number.

21356530938873 is a deficient number, since it is larger than the sum of its proper divisors (12491555841999).

21356530938873 is a wasteful number, since it uses less digits than its factorization.

21356530938873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3444046345 (or 3444046342 counting only the distinct ones).

The product of its (nonzero) digits is 97977600, while the sum is 63.

The spelling of 21356530938873 in words is "twenty-one trillion, three hundred fifty-six billion, five hundred thirty million, nine hundred thirty-eight thousand, eight hundred seventy-three".