21566670701556 has 24 divisors (see below), whose sum is σ = 50792532870240. Its totient is φ = 7121704343392.

The previous prime is 21566670701551. The next prime is 21566670701603. The reversal of 21566670701556 is 65510707666512.

It is a super-2 number, since 2×21566670701556² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21566670701496 and 21566670701505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21566670701551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8398234971 + ... + 8398237538.

It is an arithmetic number, because the mean of its divisors is an integer number (2116355536260).

Almost surely, 2^{21566670701556} is an apocalyptic number.

It is an amenable number.

21566670701556 is an abundant number, since it is smaller than the sum of its proper divisors (29225862168684).

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

21566670701556 is a wasteful number, since it uses less digits than its factorization.

21566670701556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16796472623 (or 16796472621 counting only the distinct ones).

The product of its (nonzero) digits is 15876000, while the sum is 57.

The spelling of 21566670701556 in words is "twenty-one trillion, five hundred sixty-six billion, six hundred seventy million, seven hundred one thousand, five hundred fifty-six".