21406556352 has 42 divisors (see below), whose sum is σ = 56643544828. Its totient is φ = 7134843008.

The previous prime is 21406556329. The next prime is 21406556377. The reversal of 21406556352 is 25365560412.

It is a self number, because there is not a number n which added to its sum of digits gives 21406556352.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2022049 + ... + 2032607.

Almost surely, 2^21406556352 is an apocalyptic number.

It is an amenable number.

21406556352 is an abundant number, since it is smaller than the sum of its proper divisors (35236988476).

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

21406556352 is an frugal number, since it uses more digits than its factorization.

21406556352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21133 (or 10564 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 39.

The spelling of 21406556352 in words is "twenty-one billion, four hundred six million, five hundred fifty-six thousand, three hundred fifty-two".