311005 has 4 divisors (see below), whose sum is σ = 373212. Its totient is φ = 248800.

The previous prime is 310997. The next prime is 311009. The reversal of 311005 is 500113.

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 63001 + 248004 = 251^2 + 498^2 .

It is not a de Polignac number, because 311005 - 2³ = 310997 is a prime.

It is a super-2 number, since 2×311005² = 193448220050, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

311005 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 310982 and 311000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311009) 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, 31096 + ... + 31105.

It is an arithmetic number, because the mean of its divisors is an integer number (93303).

2³¹¹⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

311005 is a deficient number, since it is larger than the sum of its proper divisors (62207).

311005 is an equidigital number, since it uses as much as digits as its factorization.

311005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62206.

The product of its (nonzero) digits is 15, while the sum is 10.

The square root of 311005 is about 557.6782226338. The cubic root of 311005 is about 67.7520526059.

Adding to 311005 its reverse (500113), we get a palindrome (811118).

The spelling of 311005 in words is "three hundred eleven thousand, five".