331921 has 2 divisors, whose sum is σ = 331922. Its totient is φ = 331920.

The previous prime is 331909. The next prime is 331937. The reversal of 331921 is 129133.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 330625 + 1296 = 575^2 + 36^2 .

It is a cyclic number.

It is not a de Polignac number, because 331921 - 2⁵ = 331889 is a prime.

It is a super-2 number, since 2×331921² = 220343100482, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (332921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165960 + 165961.

It is an arithmetic number, because the mean of its divisors is an integer number (165961).

2³³¹⁹²¹ is an apocalyptic number.

It is an amenable number.

331921 is a deficient number, since it is larger than the sum of its proper divisors (1).

331921 is an equidigital number, since it uses as much as digits as its factorization.

331921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 162, while the sum is 19.

The square root of 331921 is about 576.1258543062. The cubic root of 331921 is about 69.2380630808.

The spelling of 331921 in words is "three hundred thirty-one thousand, nine hundred twenty-one".