21328839 has 24 divisors (see below), whose sum is σ = 36516480. Its totient is φ = 12186936.

The previous prime is 21328823. The next prime is 21328873. The reversal of 21328839 is 93882312.

It is a happy number.

It is not a de Polignac number, because 21328839 - 2⁴ = 21328823 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21328819) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4569 + ... + 7970.

It is an arithmetic number, because the mean of its divisors is an integer number (1521520).

Almost surely, 2^21328839 is an apocalyptic number.

21328839 is a deficient number, since it is larger than the sum of its proper divisors (15187641).

21328839 is an equidigital number, since it uses as much as digits as its factorization.

21328839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12561 (or 12549 counting only the distinct ones).

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

The square root of 21328839 is about 4618.3156020350. The cubic root of 21328839 is about 277.3250321431.

The spelling of 21328839 in words is "twenty-one million, three hundred twenty-eight thousand, eight hundred thirty-nine".