331213217 has 2 divisors, whose sum is σ = 331213218. Its totient is φ = 331213216.

The previous prime is 331213213. The next prime is 331213237. The reversal of 331213217 is 712312133.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 182763361 + 148449856 = 13519^2 + 12184^2 .

It is a cyclic number.

It is not a de Polignac number, because 331213217 - 2² = 331213213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 331213192 and 331213201.

It is not a weakly prime, because it can be changed into another prime (331213213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165606608 + 165606609.

It is an arithmetic number, because the mean of its divisors is an integer number (165606609).

Almost surely, 2^331213217 is an apocalyptic number.

It is an amenable number.

331213217 is a deficient number, since it is larger than the sum of its proper divisors (1).

331213217 is an equidigital number, since it uses as much as digits as its factorization.

331213217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 756, while the sum is 23.

The square root of 331213217 is about 18199.2641884226. The cubic root of 331213217 is about 691.8881401436. Note that the first 3 decimals are identical.

The spelling of 331213217 in words is "three hundred thirty-one million, two hundred thirteen thousand, two hundred seventeen".