311661 has 32 divisors (see below), whose sum is σ = 564480. Its totient is φ = 165888.

The previous prime is 311659. The next prime is 311677. The reversal of 311661 is 166113.

311661 is a `hidden beast` number, since 3 + 1 + 1 + 661 = 666.

311661 is nontrivially palindromic in base 15.

It is not a de Polignac number, because 311661 - 2¹ = 311659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311681) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3165 + ... + 3261.

It is an arithmetic number, because the mean of its divisors is an integer number (17640).

2³¹¹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

311661 is a deficient number, since it is larger than the sum of its proper divisors (252819).

311661 is a wasteful number, since it uses less digits than its factorization.

311661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130 (or 124 counting only the distinct ones).

The product of its digits is 108, while the sum is 18.

The square root of 311661 is about 558.2660655995. The cubic root of 311661 is about 67.7996554137.

Adding to 311661 its reverse (166113), we get a palindrome (477774).

It can be divided in two parts, 3 and 11661, that added together give a square (11664 = 108²).

The spelling of 311661 in words is "three hundred eleven thousand, six hundred sixty-one".