161311 has 4 divisors (see below), whose sum is σ = 163072. Its totient is φ = 159552.

The previous prime is 161309. The next prime is 161323. The reversal of 161311 is 113161.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 161311 - 2¹ = 161309 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 161291 and 161300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 735 + ... + 928.

It is an arithmetic number, because the mean of its divisors is an integer number (40768).

2¹⁶¹³¹¹ is an apocalyptic number.

161311 is a deficient number, since it is larger than the sum of its proper divisors (1761).

161311 is an equidigital number, since it uses as much as digits as its factorization.

161311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1760.

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

The square root of 161311 is about 401.6354068057. The cubic root of 161311 is about 54.4362242514.

Adding to 161311 its reverse (113161), we get a palindrome (274472).

The spelling of 161311 in words is "one hundred sixty-one thousand, three hundred eleven".