312540209 has 2 divisors, whose sum is σ = 312540210. Its totient is φ = 312540208.

The previous prime is 312540197. The next prime is 312540247. The reversal of 312540209 is 902045213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 311416609 + 1123600 = 17647^2 + 1060^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-312540209 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (314540209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156270104 + 156270105.

It is an arithmetic number, because the mean of its divisors is an integer number (156270105).

Almost surely, 2^312540209 is an apocalyptic number.

It is an amenable number.

312540209 is a deficient number, since it is larger than the sum of its proper divisors (1).

312540209 is an equidigital number, since it uses as much as digits as its factorization.

312540209 is an odious number, because the sum of its binary digits is odd.

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

The square root of 312540209 is about 17678.8067753454. The cubic root of 312540209 is about 678.6335079720.

It can be divided in two parts, 3125 and 40209, that added together give a palindrome (43334).

The spelling of 312540209 in words is "three hundred twelve million, five hundred forty thousand, two hundred nine".