21302839 has 4 divisors (see below), whose sum is σ = 21334360. Its totient is φ = 21271320.

The previous prime is 21302837. The next prime is 21302881. The reversal of 21302839 is 93820312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21302839 - 2¹ = 21302837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21302833) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14724 + ... + 16105.

It is an arithmetic number, because the mean of its divisors is an integer number (5333590).

Almost surely, 2^21302839 is an apocalyptic number.

21302839 is a deficient number, since it is larger than the sum of its proper divisors (31521).

21302839 is an equidigital number, since it uses as much as digits as its factorization.

21302839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31520.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 21302839 is about 4615.4998645867. The cubic root of 21302839 is about 277.2122992890.

The spelling of 21302839 in words is "twenty-one million, three hundred two thousand, eight hundred thirty-nine".