21392959 has 6 divisors (see below), whose sum is σ = 24885744. Its totient is φ = 18336780.

The previous prime is 21392947. The next prime is 21392971. The reversal of 21392959 is 95929312.

It is an interprime number because it is at equal distance from previous prime (21392947) and next prime (21392971).

It is not a de Polignac number, because 21392959 - 2¹¹ = 21390911 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 (21392929) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 218247 + ... + 218344.

It is an arithmetic number, because the mean of its divisors is an integer number (4147624).

Almost surely, 2^21392959 is an apocalyptic number.

21392959 is a deficient number, since it is larger than the sum of its proper divisors (3492785).

21392959 is an equidigital number, since it uses as much as digits as its factorization.

21392959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436605 (or 436598 counting only the distinct ones).

The product of its digits is 43740, while the sum is 40.

The square root of 21392959 is about 4625.2523174417. The cubic root of 21392959 is about 277.6026576870.

The spelling of 21392959 in words is "twenty-one million, three hundred ninety-two thousand, nine hundred fifty-nine".