312121217 has 2 divisors, whose sum is σ = 312121218. Its totient is φ = 312121216.

The previous prime is 312121129. The next prime is 312121273. The reversal of 312121217 is 712121213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 305235841 + 6885376 = 17471^2 + 2624^2 .

It is a cyclic number.

It is not a de Polignac number, because 312121217 - 2²⁴ = 295344001 is a prime.

It is a super-2 number, since 2×312121217² = 194839308203122178, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (312120217) 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, 156060608 + 156060609.

It is an arithmetic number, because the mean of its divisors is an integer number (156060609).

Almost surely, 2^312121217 is an apocalyptic number.

It is an amenable number.

312121217 is a deficient number, since it is larger than the sum of its proper divisors (1).

312121217 is an equidigital number, since it uses as much as digits as its factorization.

312121217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 168, while the sum is 20.

The square root of 312121217 is about 17666.9526800747. The cubic root of 312121217 is about 678.3301132295.

The spelling of 312121217 in words is "three hundred twelve million, one hundred twenty-one thousand, two hundred seventeen".