21612536 has 48 divisors (see below), whose sum is σ = 45246600. Its totient is φ = 9669440.

The previous prime is 21612529. The next prime is 21612581. The reversal of 21612536 is 63521612.

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, 80210 + ... + 80478.

Almost surely, 2^21612536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21612536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22623300).

21612536 is an abundant number, since it is smaller than the sum of its proper divisors (23634064).

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

21612536 is a wasteful number, since it uses less digits than its factorization.

21612536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380 (or 365 counting only the distinct ones).

The product of its digits is 2160, while the sum is 26.

The square root of 21612536 is about 4648.9284786927. The cubic root of 21612536 is about 278.5491964099.

The spelling of 21612536 in words is "twenty-one million, six hundred twelve thousand, five hundred thirty-six".