21621566775237 has 48 divisors (see below), whose sum is σ = 34808860239552. Its totient is φ = 11769062676480.

The previous prime is 21621566775229. The next prime is 21621566775253. The reversal of 21621566775237 is 73257766512612.

It is not a de Polignac number, because 21621566775237 - 2³ = 21621566775229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621566775637) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 17820268 + ... + 18994869.

It is an arithmetic number, because the mean of its divisors is an integer number (725184588324).

Almost surely, 2^{21621566775237} is an apocalyptic number.

It is an amenable number.

21621566775237 is a deficient number, since it is larger than the sum of its proper divisors (13187293464315).

21621566775237 is a wasteful number, since it uses less digits than its factorization.

21621566775237 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36815238 (or 36815201 counting only the distinct ones).

The product of its digits is 44452800, while the sum is 60.

The spelling of 21621566775237 in words is "twenty-one trillion, six hundred twenty-one billion, five hundred sixty-six million, seven hundred seventy-five thousand, two hundred thirty-seven".