21714891 has 32 divisors (see below), whose sum is σ = 33868800. Its totient is φ = 12235680.

The previous prime is 21714887. The next prime is 21714907. The reversal of 21714891 is 19841712.

It is not a de Polignac number, because 21714891 - 2² = 21714887 is a prime.

It is a super-2 number, since 2×21714891² = 943072982283762, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21714811) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36700 + ... + 37286.

It is an arithmetic number, because the mean of its divisors is an integer number (1058400).

Almost surely, 2^21714891 is an apocalyptic number.

21714891 is a deficient number, since it is larger than the sum of its proper divisors (12153909).

21714891 is a wasteful number, since it uses less digits than its factorization.

21714891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 679.

The product of its digits is 4032, while the sum is 33.

The square root of 21714891 is about 4659.9239264177. The cubic root of 21714891 is about 278.9882319261.

The spelling of 21714891 in words is "twenty-one million, seven hundred fourteen thousand, eight hundred ninety-one".