21108732 has 24 divisors (see below), whose sum is σ = 49443072. Its totient is φ = 7009200.

The previous prime is 21108707. The next prime is 21108749. The reversal of 21108732 is 23780112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7 + ... + 6497.

It is an arithmetic number, because the mean of its divisors is an integer number (2060128).

Almost surely, 2^21108732 is an apocalyptic number.

It is an amenable number.

21108732 is an abundant number, since it is smaller than the sum of its proper divisors (28334340).

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

21108732 is a wasteful number, since it uses less digits than its factorization.

21108732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6769 (or 6767 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21108732 is about 4594.4240117778. The cubic root of 21108732 is about 276.3677622175.

Adding to 21108732 its reverse (23780112), we get a palindrome (44888844).

The spelling of 21108732 in words is "twenty-one million, one hundred eight thousand, seven hundred thirty-two".