311639 has 4 divisors (see below), whose sum is σ = 313560. Its totient is φ = 309720.

The previous prime is 311609. The next prime is 311653. The reversal of 311639 is 936113.

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 311639 - 2¹² = 307543 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 692 + ... + 1049.

It is an arithmetic number, because the mean of its divisors is an integer number (78390).

2³¹¹⁶³⁹ is an apocalyptic number.

311639 is a deficient number, since it is larger than the sum of its proper divisors (1921).

311639 is a wasteful number, since it uses less digits than its factorization.

311639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1920.

The product of its digits is 486, while the sum is 23.

The square root of 311639 is about 558.2463613854. The cubic root of 311639 is about 67.7980600612.

The spelling of 311639 in words is "three hundred eleven thousand, six hundred thirty-nine".