21404439956 has 12 divisors (see below), whose sum is σ = 37731185268. Its totient is φ = 10624101312.

The previous prime is 21404439943. The next prime is 21404439967. The reversal of 21404439956 is 65993440412.

It can be written as a sum of positive squares in 2 ways, for example, as 12697683856 + 8706756100 = 112684^2 + 93310^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21404439956.

It is a congruent 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, 19529051 + ... + 19530146.

It is an arithmetic number, because the mean of its divisors is an integer number (3144265439).

Almost surely, 2^21404439956 is an apocalyptic number.

It is an amenable number.

21404439956 is a deficient number, since it is larger than the sum of its proper divisors (16326745312).

21404439956 is a wasteful number, since it uses less digits than its factorization.

21404439956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39059338 (or 39059336 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 47.

The spelling of 21404439956 in words is "twenty-one billion, four hundred four million, four hundred thirty-nine thousand, nine hundred fifty-six".