20931239 has 8 divisors (see below), whose sum is σ = 24478080. Its totient is φ = 17523576.

The previous prime is 20931223. The next prime is 20931241. The reversal of 20931239 is 93213902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20931239 - 2⁴ = 20931223 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 (20931259) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34469 + ... + 35070.

It is an arithmetic number, because the mean of its divisors is an integer number (3059760).

Almost surely, 2^20931239 is an apocalyptic number.

20931239 is a deficient number, since it is larger than the sum of its proper divisors (3546841).

20931239 is an equidigital number, since it uses as much as digits as its factorization.

20931239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69589.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 20931239 is about 4575.0671033330. The cubic root of 20931239 is about 275.5909671353.

The spelling of 20931239 in words is "twenty million, nine hundred thirty-one thousand, two hundred thirty-nine".