331323221 has 2 divisors, whose sum is σ = 331323222. Its totient is φ = 331323220.

The previous prime is 331323151. The next prime is 331323229. The reversal of 331323221 is 122323133.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 305200900 + 26122321 = 17470^2 + 5111^2 .

It is an emirp because it is prime and its reverse (122323133) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-331323221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 331323193 and 331323202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (331323229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165661610 + 165661611.

It is an arithmetic number, because the mean of its divisors is an integer number (165661611).

Almost surely, 2^331323221 is an apocalyptic number.

It is an amenable number.

331323221 is a deficient number, since it is larger than the sum of its proper divisors (1).

331323221 is an equidigital number, since it uses as much as digits as its factorization.

331323221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 20.

The square root of 331323221 is about 18202.2861476244. The cubic root of 331323221 is about 691.9647293159.

Adding to 331323221 its reverse (122323133), we get a palindrome (453646354).

The spelling of 331323221 in words is "three hundred thirty-one million, three hundred twenty-three thousand, two hundred twenty-one".