21690992 has 20 divisors (see below), whose sum is σ = 42820920. Its totient is φ = 10640448.

The previous prime is 21690983. The next prime is 21691003. The reversal of 21690992 is 29909612.

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is a pancake number, because a pancake can be divided into 21690992 parts by 6586 straight cuts.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 11942 + ... + 13637.

It is an arithmetic number, because the mean of its divisors is an integer number (2141046).

Almost surely, 2^21690992 is an apocalyptic number.

It is an amenable number.

21690992 is a deficient number, since it is larger than the sum of its proper divisors (21129928).

21690992 is a wasteful number, since it uses less digits than its factorization.

21690992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25640 (or 25634 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 21690992 is about 4657.3589082226. The cubic root of 21690992 is about 278.8858446241.

The spelling of 21690992 in words is "twenty-one million, six hundred ninety thousand, nine hundred ninety-two".