21682971 has 40 divisors (see below), whose sum is σ = 34741520. Its totient is φ = 13436928.

The previous prime is 21682967. The next prime is 21682979. The reversal of 21682971 is 17928612.

It is not a de Polignac number, because 21682971 - 2² = 21682967 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

Its product of digits (12096) is a multiple of the sum of its prime divisors (288).

It is not an unprimeable number, because it can be changed into a prime (21682979) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 112251 + ... + 112443.

It is an arithmetic number, because the mean of its divisors is an integer number (868538).

Almost surely, 2^21682971 is an apocalyptic number.

21682971 is a deficient number, since it is larger than the sum of its proper divisors (13058549).

21682971 is a wasteful number, since it uses less digits than its factorization.

21682971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297 (or 288 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 21682971 is about 4656.4977182428. The cubic root of 21682971 is about 278.8514644669.

The spelling of 21682971 in words is "twenty-one million, six hundred eighty-two thousand, nine hundred seventy-one".