11531 has 4 divisors (see below), whose sum is σ = 12432. Its totient is φ = 10632.

The previous prime is 11527. The next prime is 11549. The reversal of 11531 is 13511.

11531 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13511 = 59 ⋅229.

It is a cyclic number.

It is not a de Polignac number, because 11531 - 2² = 11527 is a prime.

It is a super-2 number, since 2×11531² = 265927922, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 5, base 11 and base 13.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 11531.

It is not an unprimeable number, because it can be changed into a prime (11551) 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, 431 + ... + 456.

It is an arithmetic number, because the mean of its divisors is an integer number (3108).

2¹¹⁵³¹ is an apocalyptic number.

11531 is a deficient number, since it is larger than the sum of its proper divisors (901).

11531 is an equidigital number, since it uses as much as digits as its factorization.

11531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 900.

The product of its digits is 15, while the sum is 11.

The square root of 11531 is about 107.3824939178. The cubic root of 11531 is about 22.5920508760.

The spelling of 11531 in words is "eleven thousand, five hundred thirty-one".