21506832 has 60 divisors (see below), whose sum is σ = 60541884. Its totient is φ = 7127040.

The previous prime is 21506753. The next prime is 21506843. The reversal of 21506832 is 23860512.

It can be written as a sum of positive squares in 2 ways, for example, as 12362256 + 9144576 = 3516^2 + 3024^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21506796 and 21506805.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33232 + ... + 33872.

Almost surely, 2^21506832 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 21506832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30270942).

21506832 is an abundant number, since it is smaller than the sum of its proper divisors (39035052).

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

21506832 is a wasteful number, since it uses less digits than its factorization.

21506832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 888 (or 879 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 21506832 is about 4637.5459027378. The cubic root of 21506832 is about 278.0943385296.

The spelling of 21506832 in words is "twenty-one million, five hundred six thousand, eight hundred thirty-two".