21675636 has 36 divisors (see below), whose sum is σ = 56275492. Its totient is φ = 7029504.

The previous prime is 21675613. The next prime is 21675649. The reversal of 21675636 is 63657612.

21675636 is a `hidden beast` number, since 2 + 16 + 7 + 5 + 636 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 20250000 + 1425636 = 4500^2 + 1194^2 .

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

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

It is a self number, because there is not a number n which added to its sum of digits gives 21675636.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6805 + ... + 9468.

Almost surely, 2^21675636 is an apocalyptic number.

It is an amenable number.

21675636 is an abundant number, since it is smaller than the sum of its proper divisors (34599856).

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

21675636 is a wasteful number, since it uses less digits than its factorization.

21675636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16320 (or 16315 counting only the distinct ones).

The product of its digits is 45360, while the sum is 36.

The square root of 21675636 is about 4655.7100425177. The cubic root of 21675636 is about 278.8200172670.

The spelling of 21675636 in words is "twenty-one million, six hundred seventy-five thousand, six hundred thirty-six".