21356660556231 has 48 divisors (see below), whose sum is σ = 38522546076672. Its totient is φ = 10240956095040.

The previous prime is 21356660556211. The next prime is 21356660556313. The reversal of 21356660556231 is 13265506665312.

It is not a de Polignac number, because 21356660556231 - 2¹⁴ = 21356660539847 is a prime.

It is a super-2 number, since 2×21356660556231² (a number of 27 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (51) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21356660556211) 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, 323229471 + ... + 323295536.

It is an arithmetic number, because the mean of its divisors is an integer number (802553043264).

Almost surely, 2^{21356660556231} is an apocalyptic number.

21356660556231 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21356660556231 is a deficient number, since it is larger than the sum of its proper divisors (17165885520441).

21356660556231 is a wasteful number, since it uses less digits than its factorization.

21356660556231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646525052 (or 646525041 counting only the distinct ones).

The product of its (nonzero) digits is 5832000, while the sum is 51.

The spelling of 21356660556231 in words is "twenty-one trillion, three hundred fifty-six billion, six hundred sixty million, five hundred fifty-six thousand, two hundred thirty-one".