21522881756 has 12 divisors (see below), whose sum is σ = 39880633968. Its totient is φ = 10128414912.

The previous prime is 21522881701. The next prime is 21522881761. The reversal of 21522881756 is 65718822512.

It is a self number, because there is not a number n which added to its sum of digits gives 21522881756.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 158256416 + ... + 158256551.

It is an arithmetic number, because the mean of its divisors is an integer number (3323386164).

Almost surely, 2^21522881756 is an apocalyptic number.

It is an amenable number.

21522881756 is a deficient number, since it is larger than the sum of its proper divisors (18357752212).

21522881756 is a wasteful number, since it uses less digits than its factorization.

21522881756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316512988 (or 316512986 counting only the distinct ones).

The product of its digits is 537600, while the sum is 47.

The spelling of 21522881756 in words is "twenty-one billion, five hundred twenty-two million, eight hundred eighty-one thousand, seven hundred fifty-six".