311381 has 4 divisors (see below), whose sum is σ = 355872. Its totient is φ = 266892.

The previous prime is 311371. The next prime is 311393. The reversal of 311381 is 183113.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 311381 - 2¹⁰ = 310357 is a prime.

It is a super-2 number, since 2×311381² = 193916254322, which contains 22 as substring.

It is a Duffinian number.

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 311381.

It is not an unprimeable number, because it can be changed into a prime (311341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22235 + ... + 22248.

It is an arithmetic number, because the mean of its divisors is an integer number (88968).

2³¹¹³⁸¹ is an apocalyptic number.

It is an amenable number.

311381 is a deficient number, since it is larger than the sum of its proper divisors (44491).

311381 is an equidigital number, since it uses as much as digits as its factorization.

311381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44490.

The product of its digits is 72, while the sum is 17.

The square root of 311381 is about 558.0152327670. The cubic root of 311381 is about 67.7793453209.

Subtracting from 311381 its sum of digits (17), we obtain a square (311364 = 558²).

Adding to 311381 its reverse (183113), we get a palindrome (494494).

It can be divided in two parts, 3 and 11381, that multiplied together give a palindrome (34143).

The spelling of 311381 in words is "three hundred eleven thousand, three hundred eighty-one".