21987792056 has 32 divisors (see below), whose sum is σ = 41400478080. Its totient is φ = 10947736800.

The previous prime is 21987792007. The next prime is 21987792109. The reversal of 21987792056 is 65029778912.

It is a junction number, because it is equal to n+sod(n) for n = 21987791992 and 21987792010.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2909675 + ... + 2917221.

It is an arithmetic number, because the mean of its divisors is an integer number (1293764940).

Almost surely, 2^21987792056 is an apocalyptic number.

It is an amenable number.

21987792056 is a deficient number, since it is larger than the sum of its proper divisors (19412686024).

21987792056 is a wasteful number, since it uses less digits than its factorization.

21987792056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9035 (or 9031 counting only the distinct ones).

The product of its (nonzero) digits is 3810240, while the sum is 56.

The spelling of 21987792056 in words is "twenty-one billion, nine hundred eighty-seven million, seven hundred ninety-two thousand, fifty-six".