21947992 has 32 divisors (see below), whose sum is σ = 45074880. Its totient is φ = 9936160.

The previous prime is 21947977. The next prime is 21948077. The reversal of 21947992 is 29974912.

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 7 ways as a sum of consecutive naturals, for example, 38703 + ... + 39265.

It is an arithmetic number, because the mean of its divisors is an integer number (1408590).

Almost surely, 2^21947992 is an apocalyptic number.

21947992 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21947992 is an abundant number, since it is smaller than the sum of its proper divisors (23126888).

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

21947992 is a wasteful number, since it uses less digits than its factorization.

21947992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1023 (or 1019 counting only the distinct ones).

The product of its digits is 81648, while the sum is 43.

The square root of 21947992 is about 4684.8684079705. The cubic root of 21947992 is about 279.9829581465.

The spelling of 21947992 in words is "twenty-one million, nine hundred forty-seven thousand, nine hundred ninety-two".