11281 has 4 divisors (see below), whose sum is σ = 11700. Its totient is φ = 10864.

The previous prime is 11279. The next prime is 11287. The reversal of 11281 is 18211.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4225 + 7056 = 65^2 + 84^2 .

It is a cyclic number.

It is not a de Polignac number, because 11281 - 2¹ = 11279 is a prime.

It is a super-2 number, since 2×11281² = 254521922, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (11287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166 + ... + 223.

It is an arithmetic number, because the mean of its divisors is an integer number (2925).

2¹¹²⁸¹ is an apocalyptic number.

11281 is the 48-th centered decagonal number.

It is an amenable number.

11281 is a deficient number, since it is larger than the sum of its proper divisors (419).

11281 is an equidigital number, since it uses as much as digits as its factorization.

11281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418.

The product of its digits is 16, while the sum is 13.

The square root of 11281 is about 106.2120520468. The cubic root of 11281 is about 22.4275861236.

Adding to 11281 its reverse (18211), we get a palindrome (29492).

It can be divided in two parts, 11 and 281, that added together give a palindrome (292).

The spelling of 11281 in words is "eleven thousand, two hundred eighty-one".