245909 has 2 divisors, whose sum is σ = 245910. Its totient is φ = 245908.

The previous prime is 245899. The next prime is 245911. The reversal of 245909 is 909542.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 184900 + 61009 = 430^2 + 247^2 .

It is a cyclic number.

It is not a de Polignac number, because 245909 - 2⁸ = 245653 is a prime.

It is a Sophie Germain prime.

Together with 245911, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (245989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 122954 + 122955.

It is an arithmetic number, because the mean of its divisors is an integer number (122955).

2²⁴⁵⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

245909 is a deficient number, since it is larger than the sum of its proper divisors (1).

245909 is an equidigital number, since it uses as much as digits as its factorization.

245909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 245909 is about 495.8921253660. The cubic root of 245909 is about 62.6505384530.

The spelling of 245909 in words is "two hundred forty-five thousand, nine hundred nine".