21633520 has 40 divisors (see below), whose sum is σ = 53259984. Its totient is φ = 8143872.

The previous prime is 21633499. The next prime is 21633529. The reversal of 21633520 is 2533612.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 21633491 and 21633500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21633529) 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 7 ways as a sum of consecutive naturals, for example, 6594 + ... + 9313.

Almost surely, 2^21633520 is an apocalyptic number.

21633520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21633520 is an abundant number, since it is smaller than the sum of its proper divisors (31626464).

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

21633520 is a wasteful number, since it uses less digits than its factorization.

21633520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15937 (or 15931 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 22.

The square root of 21633520 is about 4651.1847952968. The cubic root of 21633520 is about 278.6393167250.

The spelling of 21633520 in words is "twenty-one million, six hundred thirty-three thousand, five hundred twenty".