21723258956 has 12 divisors (see below), whose sum is σ = 43446517968. Its totient is φ = 9309968112.

The previous prime is 21723258899. The next prime is 21723258979. The reversal of 21723258956 is 65985232712.

It is a happy number.

21723258956 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 387915311 + ... + 387915366.

It is an arithmetic number, because the mean of its divisors is an integer number (3620543164).

Almost surely, 2^21723258956 is an apocalyptic number.

It is an amenable number.

21723258956 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21723258956 is a wasteful number, since it uses less digits than its factorization.

21723258956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 775830688 (or 775830686 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 50.

The spelling of 21723258956 in words is "twenty-one billion, seven hundred twenty-three million, two hundred fifty-eight thousand, nine hundred fifty-six".