21661832 has 16 divisors (see below), whose sum is σ = 41282700. Its totient is φ = 10653120.

The previous prime is 21661831. The next prime is 21661841. The reversal of 21661832 is 23816612.

It can be written as a sum of positive squares in 2 ways, for example, as 21659716 + 2116 = 4654^2 + 46^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21661795 and 21661804.

It is not an unprimeable number, because it can be changed into a prime (21661831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21707 + ... + 22682.

Almost surely, 2^21661832 is an apocalyptic number.

It is an amenable number.

21661832 is a deficient number, since it is larger than the sum of its proper divisors (19620868).

21661832 is a wasteful number, since it uses less digits than its factorization.

21661832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44456 (or 44452 counting only the distinct ones).

The product of its digits is 3456, while the sum is 29.

The square root of 21661832 is about 4654.2273257760. The cubic root of 21661832 is about 278.7608164075.

The spelling of 21661832 in words is "twenty-one million, six hundred sixty-one thousand, eight hundred thirty-two".