21297992 has 32 divisors (see below), whose sum is σ = 41560320. Its totient is φ = 10221120.

The previous prime is 21297979. The next prime is 21298001. The reversal of 21297992 is 29979212.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38663 + ... + 39209.

It is an arithmetic number, because the mean of its divisors is an integer number (1298760).

Almost surely, 2^21297992 is an apocalyptic number.

It is an amenable number.

21297992 is a deficient number, since it is larger than the sum of its proper divisors (20262328).

21297992 is a wasteful number, since it uses less digits than its factorization.

21297992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741 (or 737 counting only the distinct ones).

The product of its digits is 40824, while the sum is 41.

The square root of 21297992 is about 4614.9747561606. The cubic root of 21297992 is about 277.1912731411.

The spelling of 21297992 in words is "twenty-one million, two hundred ninety-seven thousand, nine hundred ninety-two".