312631217 has 2 divisors, whose sum is σ = 312631218. Its totient is φ = 312631216.

The previous prime is 312631213. The next prime is 312631219. The reversal of 312631217 is 712136213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 312617761 + 13456 = 17681^2 + 116^2 .

It is an emirp because it is prime and its reverse (712136213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 312631217 - 2² = 312631213 is a prime.

Together with 312631219, 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 (312631211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156315608 + 156315609.

It is an arithmetic number, because the mean of its divisors is an integer number (156315609).

Almost surely, 2^312631217 is an apocalyptic number.

It is an amenable number.

312631217 is a deficient number, since it is larger than the sum of its proper divisors (1).

312631217 is an equidigital number, since it uses as much as digits as its factorization.

312631217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1512, while the sum is 26.

The square root of 312631217 is about 17681.3805173691. The cubic root of 312631217 is about 678.6993715876.

It can be divided in two parts, 3126 and 31217, that added together give a palindrome (34343).

The spelling of 312631217 in words is "three hundred twelve million, six hundred thirty-one thousand, two hundred seventeen".