21621992 has 32 divisors (see below), whose sum is σ = 46657920. Its totient is φ = 9201600.

The previous prime is 21621967. The next prime is 21621997. The reversal of 21621992 is 29912612.

It is not an unprimeable number, because it can be changed into a prime (21621997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7178 + ... + 9734.

It is an arithmetic number, because the mean of its divisors is an integer number (1458060).

Almost surely, 2^21621992 is an apocalyptic number.

It is an amenable number.

21621992 is an abundant number, since it is smaller than the sum of its proper divisors (25035928).

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

21621992 is a wasteful number, since it uses less digits than its factorization.

21621992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2721 (or 2717 counting only the distinct ones).

The product of its digits is 3888, while the sum is 32.

The square root of 21621992 is about 4649.9453760232. The cubic root of 21621992 is about 278.5898144591.

The spelling of 21621992 in words is "twenty-one million, six hundred twenty-one thousand, nine hundred ninety-two".