21626164 has 24 divisors (see below), whose sum is σ = 45134208. Its totient is φ = 8865120.

The previous prime is 21626153. The next prime is 21626179. The reversal of 21626164 is 46162612.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16147 + ... + 17434.

It is an arithmetic number, because the mean of its divisors is an integer number (1880592).

Almost surely, 2^21626164 is an apocalyptic number.

It is an amenable number.

21626164 is an abundant number, since it is smaller than the sum of its proper divisors (23508044).

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

21626164 is a wasteful number, since it uses less digits than its factorization.

21626164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33615 (or 33613 counting only the distinct ones).

The product of its digits is 3456, while the sum is 28.

The square root of 21626164 is about 4650.3939618058. The cubic root of 21626164 is about 278.6077314324.

Adding to 21626164 its reverse (46162612), we get a palindrome (67788776).

The spelling of 21626164 in words is "twenty-one million, six hundred twenty-six thousand, one hundred sixty-four".