21668532 has 36 divisors (see below), whose sum is σ = 52002720. Its totient is φ = 7022304.

The previous prime is 21668519. The next prime is 21668593. The reversal of 21668532 is 23586612.

It is a junction number, because it is equal to n+sod(n) for n = 21668493 and 21668502.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15769 + ... + 17087.

It is an arithmetic number, because the mean of its divisors is an integer number (1444520).

Almost surely, 2^21668532 is an apocalyptic number.

It is an amenable number.

21668532 is an abundant number, since it is smaller than the sum of its proper divisors (30334188).

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

21668532 is a wasteful number, since it uses less digits than its factorization.

21668532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1400 (or 1361 counting only the distinct ones).

The product of its digits is 17280, while the sum is 33.

The square root of 21668532 is about 4654.9470458857. The cubic root of 21668532 is about 278.7895536652.

The spelling of 21668532 in words is "twenty-one million, six hundred sixty-eight thousand, five hundred thirty-two".