331318921 has 4 divisors (see below), whose sum is σ = 331600644. Its totient is φ = 331037200.

The previous prime is 331318919. The next prime is 331318957. The reversal of 331318921 is 129813133.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 121793296 + 209525625 = 11036^2 + 14475^2 .

It is a cyclic number.

It is not a de Polignac number, because 331318921 - 2¹ = 331318919 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (331318121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 139090 + ... + 141451.

It is an arithmetic number, because the mean of its divisors is an integer number (82900161).

Almost surely, 2^331318921 is an apocalyptic number.

It is an amenable number.

331318921 is a deficient number, since it is larger than the sum of its proper divisors (281723).

331318921 is a wasteful number, since it uses less digits than its factorization.

331318921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281722.

The product of its digits is 3888, while the sum is 31.

The square root of 331318921 is about 18202.1680302100. The cubic root of 331318921 is about 691.9617358028.

The spelling of 331318921 in words is "three hundred thirty-one million, three hundred eighteen thousand, nine hundred twenty-one".