21572636 has 12 divisors (see below), whose sum is σ = 39054120. Its totient is φ = 10414320.

The previous prime is 21572623. The next prime is 21572641. The reversal of 21572636 is 63627512.

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, 92870 + ... + 93101.

It is an arithmetic number, because the mean of its divisors is an integer number (3254510).

Almost surely, 2^21572636 is an apocalyptic number.

It is an amenable number.

21572636 is a deficient number, since it is larger than the sum of its proper divisors (17481484).

21572636 is a wasteful number, since it uses less digits than its factorization.

21572636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186004 (or 186002 counting only the distinct ones).

The product of its digits is 15120, while the sum is 32.

The square root of 21572636 is about 4644.6351848127. The cubic root of 21572636 is about 278.3776762113.

The spelling of 21572636 in words is "twenty-one million, five hundred seventy-two thousand, six hundred thirty-six".