21634624 has 56 divisors (see below), whose sum is σ = 47548800. Its totient is φ = 9684480.

The previous prime is 21634607. The next prime is 21634631. The reversal of 21634624 is 42643612.

It is a junction number, because it is equal to n+sod(n) for n = 21634592 and 21634601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55422 + ... + 55810.

Almost surely, 2^21634624 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 21634624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23774400).

21634624 is an abundant number, since it is smaller than the sum of its proper divisors (25914176).

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

21634624 is a wasteful number, since it uses less digits than its factorization.

21634624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491 (or 481 counting only the distinct ones).

The product of its digits is 6912, while the sum is 28.

The square root of 21634624 is about 4651.3034732212. The cubic root of 21634624 is about 278.6440564772.

The spelling of 21634624 in words is "twenty-one million, six hundred thirty-four thousand, six hundred twenty-four".