21967856 has 10 divisors (see below), whose sum is σ = 42562752. Its totient is φ = 10983920.

The previous prime is 21967853. The next prime is 21967867. The reversal of 21967856 is 65876912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21967853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 686480 + ... + 686511.

Almost surely, 2^21967856 is an apocalyptic number.

It is an amenable number.

21967856 is a deficient number, since it is larger than the sum of its proper divisors (20594896).

21967856 is a wasteful number, since it uses less digits than its factorization.

21967856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1372999 (or 1372993 counting only the distinct ones).

The product of its digits is 181440, while the sum is 44.

The square root of 21967856 is about 4686.9879453653. The cubic root of 21967856 is about 280.0673987411.

The spelling of 21967856 in words is "twenty-one million, nine hundred sixty-seven thousand, eight hundred fifty-six".