231240509 has 2 divisors, whose sum is σ = 231240510. Its totient is φ = 231240508.

The previous prime is 231240481. The next prime is 231240521. The reversal of 231240509 is 905042132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 226051225 + 5189284 = 15035^2 + 2278^2 .

It is a cyclic number.

It is not a de Polignac number, because 231240509 - 2²⁰ = 230191933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231240599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115620254 + 115620255.

It is an arithmetic number, because the mean of its divisors is an integer number (115620255).

Almost surely, 2^231240509 is an apocalyptic number.

It is an amenable number.

231240509 is a deficient number, since it is larger than the sum of its proper divisors (1).

231240509 is an equidigital number, since it uses as much as digits as its factorization.

231240509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 231240509 is about 15206.5942603859. The cubic root of 231240509 is about 613.7921157478.

The spelling of 231240509 in words is "two hundred thirty-one million, two hundred forty thousand, five hundred nine".