331861 has 4 divisors (see below), whose sum is σ = 333324. Its totient is φ = 330400.

The previous prime is 331843. The next prime is 331871. The reversal of 331861 is 168133.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 168133 = 7 ⋅24019.

It can be written as a sum of positive squares in 2 ways, for example, as 269361 + 62500 = 519^2 + 250^2 .

It is a cyclic number.

It is not a de Polignac number, because 331861 - 2⁹ = 331349 is a prime.

It is a super-2 number, since 2×331861² = 220263446642, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (331801) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 310 + ... + 871.

It is an arithmetic number, because the mean of its divisors is an integer number (83331).

2³³¹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

331861 is a deficient number, since it is larger than the sum of its proper divisors (1463).

331861 is a wasteful number, since it uses less digits than its factorization.

331861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1462.

The product of its digits is 432, while the sum is 22.

The square root of 331861 is about 576.0737799970. The cubic root of 331861 is about 69.2338908691.

Adding to 331861 its reverse (168133), we get a palindrome (499994).

The spelling of 331861 in words is "three hundred thirty-one thousand, eight hundred sixty-one".