21405274008 has 16 divisors (see below), whose sum is σ = 53513185080. Its totient is φ = 7135091328.

The previous prime is 21405273997. The next prime is 21405274031. The reversal of 21405274008 is 80047250412.

It is a self number, because there is not a number n which added to its sum of digits gives 21405274008.

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, 445943185 + ... + 445943232.

Almost surely, 2^21405274008 is an apocalyptic number.

It is an amenable number.

21405274008 is an abundant number, since it is smaller than the sum of its proper divisors (32107911072).

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

21405274008 is a wasteful number, since it uses less digits than its factorization.

21405274008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 891886426 (or 891886422 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 33.

The spelling of 21405274008 in words is "twenty-one billion, four hundred five million, two hundred seventy-four thousand, eight".