21091054056 has 32 divisors (see below), whose sum is σ = 54152708640. Its totient is φ = 6840341568.

The previous prime is 21091054043. The next prime is 21091054123. The reversal of 21091054056 is 65045019012.

It is a super-2 number, since 2×21091054056² (a number of 21 digits) contains 22 as substring.

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, 11874706 + ... + 11876481.

It is an arithmetic number, because the mean of its divisors is an integer number (1692272145).

Almost surely, 2^21091054056 is an apocalyptic number.

It is an amenable number.

21091054056 is an abundant number, since it is smaller than the sum of its proper divisors (33061654584).

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

21091054056 is a wasteful number, since it uses less digits than its factorization.

21091054056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23751233 (or 23751229 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 33.

The spelling of 21091054056 in words is "twenty-one billion, ninety-one million, fifty-four thousand, fifty-six".