21868887 has 16 divisors (see below), whose sum is σ = 30098432. Its totient is φ = 14113440.

The previous prime is 21868849. The next prime is 21868909. The reversal of 21868887 is 78886812.

It is not a de Polignac number, because 21868887 - 2⁸ = 21868631 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 (21868087) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29718 + ... + 30444.

It is an arithmetic number, because the mean of its divisors is an integer number (1881152).

Almost surely, 2^21868887 is an apocalyptic number.

21868887 is a deficient number, since it is larger than the sum of its proper divisors (8229545).

21868887 is a wasteful number, since it uses less digits than its factorization.

21868887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1038.

The product of its digits is 344064, while the sum is 48.

The square root of 21868887 is about 4676.4181806164. The cubic root of 21868887 is about 279.6461814913.

The spelling of 21868887 in words is "twenty-one million, eight hundred sixty-eight thousand, eight hundred eighty-seven".