181281 has 4 divisors (see below), whose sum is σ = 241712. Its totient is φ = 120852.

The previous prime is 181277. The next prime is 181283. The reversal of 181281 is 182181.

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, and also an emirpimes, since its reverse is a distinct semiprime: 182181 = 3 ⋅60727.

It is not a de Polignac number, because 181281 - 2² = 181277 is a prime.

It is a super-2 number, since 2×181281² = 65725601922, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 181281.

It is not an unprimeable number, because it can be changed into a prime (181283) 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, 30211 + ... + 30216.

It is an arithmetic number, because the mean of its divisors is an integer number (60428).

2¹⁸¹²⁸¹ is an apocalyptic number.

It is an amenable number.

181281 is a deficient number, since it is larger than the sum of its proper divisors (60431).

181281 is an equidigital number, since it uses as much as digits as its factorization.

181281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60430.

The product of its digits is 128, while the sum is 21.

The square root of 181281 is about 425.7710652452. The cubic root of 181281 is about 56.5957860406.

Subtracting 181281 from its reverse (182181), we obtain a square (900 = 30²).

The spelling of 181281 in words is "one hundred eighty-one thousand, two hundred eighty-one".