21056781926 has 8 divisors (see below), whose sum is σ = 31633992720. Its totient is φ = 10512117688.

The previous prime is 21056781923. The next prime is 21056781943. The reversal of 21056781926 is 62918765012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056781923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8135021 + ... + 8137608.

It is an arithmetic number, because the mean of its divisors is an integer number (3954249090).

Almost surely, 2^21056781926 is an apocalyptic number.

21056781926 is a deficient number, since it is larger than the sum of its proper divisors (10577210794).

21056781926 is a wasteful number, since it uses less digits than its factorization.

21056781926 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16273278.

The product of its (nonzero) digits is 362880, while the sum is 47.

The spelling of 21056781926 in words is "twenty-one billion, fifty-six million, seven hundred eighty-one thousand, nine hundred twenty-six".