311161 has 4 divisors (see below), whose sum is σ = 316324. Its totient is φ = 306000.

The previous prime is 311153. The next prime is 311173. The reversal of 311161 is 161113.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 161113 = 367 ⋅439.

It can be written as a sum of positive squares in 2 ways, for example, as 3136 + 308025 = 56^2 + 555^2 .

It is a cyclic number.

It is not a de Polignac number, because 311161 - 2³ = 311153 is a prime.

It is a Duffinian number.

311161 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2490 + ... + 2611.

It is an arithmetic number, because the mean of its divisors is an integer number (79081).

2³¹¹¹⁶¹ is an apocalyptic number.

It is an amenable number.

311161 is a deficient number, since it is larger than the sum of its proper divisors (5163).

311161 is an equidigital number, since it uses as much as digits as its factorization.

311161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5162.

The product of its digits is 18, while the sum is 13.

The square root of 311161 is about 557.8180707005. The cubic root of 311161 is about 67.7633788478.

Adding to 311161 its reverse (161113), we get a palindrome (472274).

The spelling of 311161 in words is "three hundred eleven thousand, one hundred sixty-one".