21632520 has 192 divisors, whose sum is σ = 81587520. Its totient is φ = 4548096.

The previous prime is 21632509. The next prime is 21632537. The reversal of 21632520 is 2523612.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 76299 + ... + 76581.

It is an arithmetic number, because the mean of its divisors is an integer number (424935).

Almost surely, 2^21632520 is an apocalyptic number.

21632520 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 21632520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40793760).

21632520 is an abundant number, since it is smaller than the sum of its proper divisors (59955000).

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

21632520 is a wasteful number, since it uses less digits than its factorization.

21632520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324 (or 313 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21632520 is about 4651.0772945631. The cubic root of 21632520 is about 278.6350233320.

The spelling of 21632520 in words is "twenty-one million, six hundred thirty-two thousand, five hundred twenty".