21636522 has 12 divisors (see below), whose sum is σ = 46879170. Its totient is φ = 7212168.

The previous prime is 21636521. The next prime is 21636533. The reversal of 21636522 is 22563612.

21636522 is a `hidden beast` number, since 2 + 1 + 6 + 3 + 652 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 18844281 + 2792241 = 4341^2 + 1671^2 .

It is not an unprimeable number, because it can be changed into a prime (21636521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 600997 + ... + 601032.

Almost surely, 2^21636522 is an apocalyptic number.

21636522 is an abundant number, since it is smaller than the sum of its proper divisors (25242648).

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

21636522 is a wasteful number, since it uses less digits than its factorization.

21636522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1202037 (or 1202034 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The square root of 21636522 is about 4651.5074975754. The cubic root of 21636522 is about 278.6522046960.

The spelling of 21636522 in words is "twenty-one million, six hundred thirty-six thousand, five hundred twenty-two".