21328938 has 24 divisors (see below), whose sum is σ = 47341476. Its totient is φ = 6936000.

The previous prime is 21328927. The next prime is 21328943. The reversal of 21328938 is 83982312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21095649 + 233289 = 4593^2 + 483^2 .

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, 13713 + ... + 15188.

Almost surely, 2^21328938 is an apocalyptic number.

21328938 is an abundant number, since it is smaller than the sum of its proper divisors (26012538).

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

21328938 is a wasteful number, since it uses less digits than its factorization.

21328938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28950 (or 28947 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 21328938 is about 4618.3263202160. The cubic root of 21328938 is about 277.3254612200.

The spelling of 21328938 in words is "twenty-one million, three hundred twenty-eight thousand, nine hundred thirty-eight".