181331 has 4 divisors (see below), whose sum is σ = 185592. Its totient is φ = 177072.

The previous prime is 181303. The next prime is 181361. The reversal of 181331 is 133181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 133181 = 97 ⋅1373.

It is a cyclic number.

It is not a de Polignac number, because 181331 - 2¹⁰ = 180307 is a prime.

It is a super-2 number, since 2×181331² = 65761863122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181301) 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, 2066 + ... + 2151.

It is an arithmetic number, because the mean of its divisors is an integer number (46398).

2¹⁸¹³³¹ is an apocalyptic number.

181331 is a deficient number, since it is larger than the sum of its proper divisors (4261).

181331 is an equidigital number, since it uses as much as digits as its factorization.

181331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4260.

The product of its digits is 72, while the sum is 17.

The square root of 181331 is about 425.8297781978. The cubic root of 181331 is about 56.6009888826.

It can be divided in two parts, 181 and 331, that added together give a 9-th power (512 = 2⁹).

The spelling of 181331 in words is "one hundred eighty-one thousand, three hundred thirty-one".