21666832 has 40 divisors (see below), whose sum is σ = 46059552. Its totient is φ = 9792000.

The previous prime is 21666829. The next prime is 21666863. The reversal of 21666832 is 23866612.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53832 + ... + 54232.

Almost surely, 2^21666832 is an apocalyptic number.

21666832 is a gapful number since it is divisible by the number (22) 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 21666832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23029776).

21666832 is an abundant number, since it is smaller than the sum of its proper divisors (24392720).

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

21666832 is a wasteful number, since it uses less digits than its factorization.

21666832 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 727 (or 721 counting only the distinct ones).

The product of its digits is 20736, while the sum is 34.

The square root of 21666832 is about 4654.7644408713. The cubic root of 21666832 is about 278.7822626831.

It can be divided in two parts, 2166 and 6832, that added together give a palindrome (8998).

The spelling of 21666832 in words is "twenty-one million, six hundred sixty-six thousand, eight hundred thirty-two".