21506632 has 128 divisors (see below), whose sum is σ = 54432000. Its totient is φ = 7741440.

The previous prime is 21506629. The next prime is 21506647. The reversal of 21506632 is 23660512.

It is a junction number, because it is equal to n+sod(n) for n = 21506597 and 21506606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 524532 + ... + 524572.

It is an arithmetic number, because the mean of its divisors is an integer number (425250).

Almost surely, 2^21506632 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 21506632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27216000).

21506632 is an abundant number, since it is smaller than the sum of its proper divisors (32925368).

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

21506632 is a wasteful number, since it uses less digits than its factorization.

21506632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 21506632 is about 4637.5243395588. The cubic root of 21506632 is about 278.0934764928.

The spelling of 21506632 in words is "twenty-one million, five hundred six thousand, six hundred thirty-two".