21556992 has 36 divisors (see below), whose sum is σ = 57375080. Its totient is φ = 7185408.

The previous prime is 21556987. The next prime is 21556999. The reversal of 21556992 is 29965512.

It is a self number, because there is not a number n which added to its sum of digits gives 21556992.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21556999) 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, 13267 + ... + 14802.

Almost surely, 2^21556992 is an apocalyptic number.

It is an amenable number.

21556992 is an abundant number, since it is smaller than the sum of its proper divisors (35818088).

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

21556992 is an equidigital number, since it uses as much as digits as its factorization.

21556992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28088 (or 28074 counting only the distinct ones).

The product of its digits is 48600, while the sum is 39.

The square root of 21556992 is about 4642.9507858688. The cubic root of 21556992 is about 278.3103688210.

The spelling of 21556992 in words is "twenty-one million, five hundred fifty-six thousand, nine hundred ninety-two".