20439239 has 4 divisors (see below), whose sum is σ = 20488440. Its totient is φ = 20390040.

The previous prime is 20439191. The next prime is 20439257. The reversal of 20439239 is 93293402.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20439239 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 (20439299) 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, 23972 + ... + 24809.

It is an arithmetic number, because the mean of its divisors is an integer number (5122110).

Almost surely, 2^20439239 is an apocalyptic number.

20439239 is a deficient number, since it is larger than the sum of its proper divisors (49201).

20439239 is an equidigital number, since it uses as much as digits as its factorization.

20439239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49200.

The product of its (nonzero) digits is 11664, while the sum is 32.

The square root of 20439239 is about 4520.9776597546. The cubic root of 20439239 is about 273.4145196404.

The spelling of 20439239 in words is "twenty million, four hundred thirty-nine thousand, two hundred thirty-nine".