21877164 has 36 divisors (see below), whose sum is σ = 58555224. Its totient is φ = 6863232.

The previous prime is 21877157. The next prime is 21877169. The reversal of 21877164 is 46177812.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×21877164² = 957220609365792, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21877169) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 17262 + ... + 18485.

It is an arithmetic number, because the mean of its divisors is an integer number (1626534).

Almost surely, 2^21877164 is an apocalyptic number.

It is an amenable number.

21877164 is an abundant number, since it is smaller than the sum of its proper divisors (36678060).

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

21877164 is a wasteful number, since it uses less digits than its factorization.

21877164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35774 (or 35769 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 21877164 is about 4677.3030690773. The cubic root of 21877164 is about 279.6814574748.

The spelling of 21877164 in words is "twenty-one million, eight hundred seventy-seven thousand, one hundred sixty-four".