331222721 has 2 divisors, whose sum is σ = 331222722. Its totient is φ = 331222720.

The previous prime is 331222711. The next prime is 331222757. The reversal of 331222721 is 127222133.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 248503696 + 82719025 = 15764^2 + 9095^2 .

It is an emirp because it is prime and its reverse (127222133) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 331222721 - 2⁶ = 331222657 is a prime.

It is not a weakly prime, because it can be changed into another prime (331222711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165611360 + 165611361.

It is an arithmetic number, because the mean of its divisors is an integer number (165611361).

Almost surely, 2^331222721 is an apocalyptic number.

It is an amenable number.

331222721 is a deficient number, since it is larger than the sum of its proper divisors (1).

331222721 is an equidigital number, since it uses as much as digits as its factorization.

331222721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 23.

The square root of 331222721 is about 18199.5252960070. The cubic root of 331222721 is about 691.8947578767.

Adding to 331222721 its reverse (127222133), we get a palindrome (458444854).

The spelling of 331222721 in words is "three hundred thirty-one million, two hundred twenty-two thousand, seven hundred twenty-one".