21668832 has 36 divisors (see below), whose sum is σ = 61621560. Its totient is φ = 7222848.

The previous prime is 21668827. The next prime is 21668839. The reversal of 21668832 is 23886612.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21668839) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 37332 + ... + 37907.

It is an arithmetic number, because the mean of its divisors is an integer number (1711710).

Almost surely, 2^21668832 is an apocalyptic number.

It is an amenable number.

21668832 is an abundant number, since it is smaller than the sum of its proper divisors (39952728).

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

21668832 is a wasteful number, since it uses less digits than its factorization.

21668832 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75255 (or 75244 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 21668832 is about 4654.9792695564. The cubic root of 21668832 is about 278.7908402695.

It can be divided in two parts, 21668 and 832, that added together give a square (22500 = 150²).

The spelling of 21668832 in words is "twenty-one million, six hundred sixty-eight thousand, eight hundred thirty-two".