311905 has 16 divisors (see below), whose sum is σ = 419904. Its totient is φ = 220480.

The previous prime is 311897. The next prime is 311951. The reversal of 311905 is 509113.

It is not a de Polignac number, because 311905 - 2³ = 311897 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 2862 + ... + 2968.

It is an arithmetic number, because the mean of its divisors is an integer number (26244).

2³¹¹⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

311905 is a deficient number, since it is larger than the sum of its proper divisors (107999).

311905 is a wasteful number, since it uses less digits than its factorization.

311905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176.

The product of its (nonzero) digits is 135, while the sum is 19.

The square root of 311905 is about 558.4845566352. The cubic root of 311905 is about 67.8173442921.

It can be divided in two parts, 31 and 1905, that added together give a square (1936 = 44²).

The spelling of 311905 in words is "three hundred eleven thousand, nine hundred five".