21322164 has 12 divisors (see below), whose sum is σ = 49751744. Its totient is φ = 7107384.

The previous prime is 21322139. The next prime is 21322181. The reversal of 21322164 is 46122312.

It is a tau number, because it is divible by the number of its divisors (12).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21322164.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 888412 + ... + 888435.

Almost surely, 2^21322164 is an apocalyptic number.

It is an amenable number.

21322164 is an abundant number, since it is smaller than the sum of its proper divisors (28429580).

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

21322164 is a wasteful number, since it uses less digits than its factorization.

21322164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1776854 (or 1776852 counting only the distinct ones).

The product of its digits is 576, while the sum is 21.

The square root of 21322164 is about 4617.5928794124. The cubic root of 21322164 is about 277.2960988956.

Adding to 21322164 its reverse (46122312), we get a palindrome (67444476).

The spelling of 21322164 in words is "twenty-one million, three hundred twenty-two thousand, one hundred sixty-four".