21633536 has 80 divisors (see below), whose sum is σ = 47139840. Its totient is φ = 9891840.

The previous prime is 21633529. The next prime is 21633539. The reversal of 21633536 is 63533612.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a junction number, because it is equal to n+sod(n) for n = 21633499 and 21633508.

It is not an unprimeable number, because it can be changed into a prime (21633539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 460265 + ... + 460311.

It is an arithmetic number, because the mean of its divisors is an integer number (589248).

Almost surely, 2^21633536 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 21633536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23569920).

21633536 is an abundant number, since it is smaller than the sum of its proper divisors (25506304).

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

21633536 is an equidigital number, since it uses as much as digits as its factorization.

21633536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 109 counting only the distinct ones).

The product of its digits is 9720, while the sum is 29.

The square root of 21633536 is about 4651.1865152883. The cubic root of 21633536 is about 278.6393854182.

The spelling of 21633536 in words is "twenty-one million, six hundred thirty-three thousand, five hundred thirty-six".