20418239 has 2 divisors, whose sum is σ = 20418240. Its totient is φ = 20418238.

The previous prime is 20418199. The next prime is 20418247. The reversal of 20418239 is 93281402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20418239 - 2²⁰ = 19369663 is a prime.

It is a super-2 number, since 2×20418239² = 833808967722242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20418439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10209119 + 10209120.

It is an arithmetic number, because the mean of its divisors is an integer number (10209120).

Almost surely, 2^20418239 is an apocalyptic number.

20418239 is a deficient number, since it is larger than the sum of its proper divisors (1).

20418239 is an equidigital number, since it uses as much as digits as its factorization.

20418239 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 20418239 is about 4518.6545563918. The cubic root of 20418239 is about 273.3208489572.

The spelling of 20418239 in words is "twenty million, four hundred eighteen thousand, two hundred thirty-nine".