135523 has 4 divisors (see below), whose sum is σ = 137880. Its totient is φ = 133168.

The previous prime is 135511. The next prime is 135533. The reversal of 135523 is 325531.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 325531 = 31 ⋅10501.

It is a cyclic number.

It is not a de Polignac number, because 135523 - 2¹³ = 127331 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 135523.

It is not an unprimeable number, because it can be changed into a prime (135533) 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, 1090 + ... + 1207.

It is an arithmetic number, because the mean of its divisors is an integer number (34470).

2¹³⁵⁵²³ is an apocalyptic number.

135523 is a deficient number, since it is larger than the sum of its proper divisors (2357).

135523 is an equidigital number, since it uses as much as digits as its factorization.

135523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2356.

The product of its digits is 450, while the sum is 19.

The square root of 135523 is about 368.1344862954. The cubic root of 135523 is about 51.3654387718.

It can be divided in two parts, 1355 and 23, that added together give a triangular number (1378 = T₅₂).

The spelling of 135523 in words is "one hundred thirty-five thousand, five hundred twenty-three".