135531 has 18 divisors (see below), whose sum is σ = 219492. Its totient is φ = 79920.

The previous prime is 135511. The next prime is 135533.

It is a happy number.

135531 is a `hidden beast` number, since 135 + 531 = 666.

135531 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 135531 - 2⁶ = 135467 is a prime.

It is a super-2 number, since 2×135531² = 36737303922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (135533) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3645 + ... + 3681.

It is an arithmetic number, because the mean of its divisors is an integer number (12194).

2¹³⁵⁵³¹ is an apocalyptic number.

135531 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

135531 is a deficient number, since it is larger than the sum of its proper divisors (83961).

135531 is a wasteful number, since it uses less digits than its factorization.

135531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 51 counting only the distinct ones).

The product of its digits is 225, while the sum is 18.

The square root of 135531 is about 368.1453517294. The cubic root of 135531 is about 51.3664494623.

It can be divided in two parts, 135 and 531, that added together give a palindrome (666).

The spelling of 135531 in words is "one hundred thirty-five thousand, five hundred thirty-one".