21863568 has 20 divisors (see below), whose sum is σ = 56481008. Its totient is φ = 7287840.

The previous prime is 21863563. The next prime is 21863599. The reversal of 21863568 is 86536812.

It is a happy number.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21863561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227698 + ... + 227793.

Almost surely, 2^21863568 is an apocalyptic number.

It is an amenable number.

21863568 is an abundant number, since it is smaller than the sum of its proper divisors (34617440).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21863568 is a wasteful number, since it uses less digits than its factorization.

21863568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455502 (or 455496 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 21863568 is about 4675.8494415454. The cubic root of 21863568 is about 279.6235075947.

The spelling of 21863568 in words is "twenty-one million, eight hundred sixty-three thousand, five hundred sixty-eight".