251939 has 2 divisors, whose sum is σ = 251940. Its totient is φ = 251938.

The previous prime is 251917. The next prime is 251941. The reversal of 251939 is 939152.

251939 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-251939 is a prime.

It is a Sophie Germain prime.

Together with 251941, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (251969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125969 + 125970.

It is an arithmetic number, because the mean of its divisors is an integer number (125970).

2²⁵¹⁹³⁹ is an apocalyptic number.

251939 is a deficient number, since it is larger than the sum of its proper divisors (1).

251939 is an equidigital number, since it uses as much as digits as its factorization.

251939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2430, while the sum is 29.

The square root of 251939 is about 501.9352547889. The cubic root of 251939 is about 63.1584990317.

The spelling of 251939 in words is "two hundred fifty-one thousand, nine hundred thirty-nine".