331561 has 4 divisors (see below), whose sum is σ = 334224. Its totient is φ = 328900.

The previous prime is 331553. The next prime is 331577. The reversal of 331561 is 165133.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 331561 - 2³ = 331553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (331501) 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, 1135 + ... + 1396.

It is an arithmetic number, because the mean of its divisors is an integer number (83556).

2³³¹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

331561 is a deficient number, since it is larger than the sum of its proper divisors (2663).

331561 is a wasteful number, since it uses less digits than its factorization.

331561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2662.

The product of its digits is 270, while the sum is 19.

The square root of 331561 is about 575.8133378101. The cubic root of 331561 is about 69.2130222633.

Adding to 331561 its reverse (165133), we get a palindrome (496694).

The spelling of 331561 in words is "three hundred thirty-one thousand, five hundred sixty-one".