312221321 has 2 divisors, whose sum is σ = 312221322. Its totient is φ = 312221320.

The previous prime is 312221317. The next prime is 312221353. The reversal of 312221321 is 123122213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 270438025 + 41783296 = 16445^2 + 6464^2 .

It is a cyclic number.

It is not a de Polignac number, because 312221321 - 2² = 312221317 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 312221321.

It is not a weakly prime, because it can be changed into another prime (312221521) 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, 156110660 + 156110661.

It is an arithmetic number, because the mean of its divisors is an integer number (156110661).

Almost surely, 2^312221321 is an apocalyptic number.

It is an amenable number.

312221321 is a deficient number, since it is larger than the sum of its proper divisors (1).

312221321 is an equidigital number, since it uses as much as digits as its factorization.

312221321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 17.

The square root of 312221321 is about 17669.7855391626. The cubic root of 312221321 is about 678.4026238396.

Adding to 312221321 its reverse (123122213), we get a palindrome (435343534).

The spelling of 312221321 in words is "three hundred twelve million, two hundred twenty-one thousand, three hundred twenty-one".