312551221 has 2 divisors, whose sum is σ = 312551222. Its totient is φ = 312551220.

The previous prime is 312551203. The next prime is 312551227. The reversal of 312551221 is 122155213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 159138225 + 153412996 = 12615^2 + 12386^2 .

It is an emirp because it is prime and its reverse (122155213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 312551221 - 2⁵ = 312551189 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 312551192 and 312551201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (312551227) 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, 156275610 + 156275611.

It is an arithmetic number, because the mean of its divisors is an integer number (156275611).

Almost surely, 2^312551221 is an apocalyptic number.

It is an amenable number.

312551221 is a deficient number, since it is larger than the sum of its proper divisors (1).

312551221 is an equidigital number, since it uses as much as digits as its factorization.

312551221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 600, while the sum is 22.

The square root of 312551221 is about 17679.1182189610. The cubic root of 312551221 is about 678.6414781725.

The spelling of 312551221 in words is "three hundred twelve million, five hundred fifty-one thousand, two hundred twenty-one".