331391 has 2 divisors, whose sum is σ = 331392. Its totient is φ = 331390.

The previous prime is 331369. The next prime is 331399. The reversal of 331391 is 193133.

It is a strong prime.

It is an emirp because it is prime and its reverse (193133) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 331391 - 2¹⁸ = 69247 is a prime.

It is a Chen prime.

It is an Ulam number.

It is a plaindrome in base 14.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 331391.

It is not a weakly prime, because it can be changed into another prime (331399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165695 + 165696.

It is an arithmetic number, because the mean of its divisors is an integer number (165696).

2³³¹³⁹¹ is an apocalyptic number.

331391 is a deficient number, since it is larger than the sum of its proper divisors (1).

331391 is an equidigital number, since it uses as much as digits as its factorization.

331391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 243, while the sum is 20.

The square root of 331391 is about 575.6657016012. The cubic root of 331391 is about 69.2011911319.

The spelling of 331391 in words is "three hundred thirty-one thousand, three hundred ninety-one".