21356164 has 12 divisors (see below), whose sum is σ = 37414300. Its totient is φ = 10666368.

The previous prime is 21356143. The next prime is 21356177. The reversal of 21356164 is 46165312.

It can be written as a sum of positive squares in 2 ways, for example, as 1016064 + 20340100 = 1008^2 + 4510^2 .

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, 2152 + ... + 6880.

Almost surely, 2^21356164 is an apocalyptic number.

It is an amenable number.

21356164 is a deficient number, since it is larger than the sum of its proper divisors (16058136).

21356164 is a wasteful number, since it uses less digits than its factorization.

21356164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5862 (or 5860 counting only the distinct ones).

The product of its digits is 4320, while the sum is 28.

The square root of 21356164 is about 4621.2729847954. The cubic root of 21356164 is about 277.4434113434.

The spelling of 21356164 in words is "twenty-one million, three hundred fifty-six thousand, one hundred sixty-four".