331290221 has 2 divisors, whose sum is σ = 331290222. Its totient is φ = 331290220.

The previous prime is 331290187. The next prime is 331290241. The reversal of 331290221 is 122092133.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 324504196 + 6786025 = 18014^2 + 2605^2 .

It is a cyclic number.

It is not a de Polignac number, because 331290221 - 2²² = 327095917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (331290241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165645110 + 165645111.

It is an arithmetic number, because the mean of its divisors is an integer number (165645111).

Almost surely, 2^331290221 is an apocalyptic number.

It is an amenable number.

331290221 is a deficient number, since it is larger than the sum of its proper divisors (1).

331290221 is an equidigital number, since it uses as much as digits as its factorization.

331290221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 331290221 is about 18201.3796455104. The cubic root of 331290221 is about 691.9417551799.

The spelling of 331290221 in words is "three hundred thirty-one million, two hundred ninety thousand, two hundred twenty-one".