21863936 has 20 divisors (see below), whose sum is σ = 43686192. Its totient is φ = 10931712.

The previous prime is 21863923. The next prime is 21863951. The reversal of 21863936 is 63936812.

It is a self number, because there is not a number n which added to its sum of digits gives 21863936.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20840 + ... + 21863.

Almost surely, 2^21863936 is an apocalyptic number.

It is an amenable number.

21863936 is a deficient number, since it is larger than the sum of its proper divisors (21822256).

21863936 is an frugal number, since it uses more digits than its factorization.

21863936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42721 (or 42705 counting only the distinct ones).

The product of its digits is 46656, while the sum is 38.

The square root of 21863936 is about 4675.8887925185. Note that the first 3 decimals coincide. The cubic root of 21863936 is about 279.6250764279.

The spelling of 21863936 in words is "twenty-one million, eight hundred sixty-three thousand, nine hundred thirty-six".