21971372 has 24 divisors (see below), whose sum is σ = 41341440. Its totient is φ = 10184400.

The previous prime is 21971359. The next prime is 21971387. The reversal of 21971372 is 27317912.

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, 497 + ... + 6647.

It is an arithmetic number, because the mean of its divisors is an integer number (1722560).

Almost surely, 2^21971372 is an apocalyptic number.

It is an amenable number.

21971372 is a deficient number, since it is larger than the sum of its proper divisors (19370068).

21971372 is a wasteful number, since it uses less digits than its factorization.

21971372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6221 (or 6219 counting only the distinct ones).

The product of its digits is 5292, while the sum is 32.

The square root of 21971372 is about 4687.3630113316. The cubic root of 21971372 is about 280.0823397295.

The spelling of 21971372 in words is "twenty-one million, nine hundred seventy-one thousand, three hundred seventy-two".