21624980 has 48 divisors (see below), whose sum is σ = 50502144. Its totient is φ = 7724160.

The previous prime is 21624973. The next prime is 21625027. The reversal of 21624980 is 8942612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6719 + ... + 9401.

It is an arithmetic number, because the mean of its divisors is an integer number (1052128).

Almost surely, 2^21624980 is an apocalyptic number.

21624980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21624980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25251072).

21624980 is an abundant number, since it is smaller than the sum of its proper divisors (28877164).

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

21624980 is a wasteful number, since it uses less digits than its factorization.

21624980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2736 (or 2734 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 21624980 is about 4650.2666590207. The cubic root of 21624980 is about 278.6026468880.

The spelling of 21624980 in words is "twenty-one million, six hundred twenty-four thousand, nine hundred eighty".