21868715 has 32 divisors (see below), whose sum is σ = 31933440. Its totient is φ = 14169600.

The previous prime is 21868709. The next prime is 21868723. The reversal of 21868715 is 51786812.

It is not a de Polignac number, because 21868715 - 2⁸ = 21868459 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17150 + ... + 18380.

It is an arithmetic number, because the mean of its divisors is an integer number (997920).

Almost surely, 2^21868715 is an apocalyptic number.

21868715 is a deficient number, since it is larger than the sum of its proper divisors (10064725).

21868715 is a wasteful number, since it uses less digits than its factorization.

21868715 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1283.

The product of its digits is 26880, while the sum is 38.

The square root of 21868715 is about 4676.3997904371. The cubic root of 21868715 is about 279.6454483452.

It can be divided in two parts, 2186 and 8715, that added together give a palindrome (10901).

The spelling of 21868715 in words is "twenty-one million, eight hundred sixty-eight thousand, seven hundred fifteen".