21694671 has 6 divisors (see below), whose sum is σ = 31336760. Its totient is φ = 14463108.

The previous prime is 21694663. The next prime is 21694679. The reversal of 21694671 is 17649612.

It is an interprime number because it is at equal distance from previous prime (21694663) and next prime (21694679).

It is not a de Polignac number, because 21694671 - 2³ = 21694663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21694679) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1205251 + ... + 1205268.

Almost surely, 2^21694671 is an apocalyptic number.

21694671 is a deficient number, since it is larger than the sum of its proper divisors (9642089).

21694671 is a wasteful number, since it uses less digits than its factorization.

21694671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2410525 (or 2410522 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 21694671 is about 4657.7538578160. The cubic root of 21694671 is about 278.9016109696.

The spelling of 21694671 in words is "twenty-one million, six hundred ninety-four thousand, six hundred seventy-one".