135591 has 4 divisors (see below), whose sum is σ = 180792. Its totient is φ = 90392.

The previous prime is 135589. The next prime is 135593. The reversal of 135591 is 195531.

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

It is an interprime number because it is at equal distance from previous prime (135589) and next prime (135593).

It is a cyclic number.

It is not a de Polignac number, because 135591 - 2¹ = 135589 is a prime.

It is a D-number.

135591 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135593) 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, 22596 + ... + 22601.

It is an arithmetic number, because the mean of its divisors is an integer number (45198).

2¹³⁵⁵⁹¹ is an apocalyptic number.

135591 is a deficient number, since it is larger than the sum of its proper divisors (45201).

135591 is an equidigital number, since it uses as much as digits as its factorization.

135591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45200.

The product of its digits is 675, while the sum is 24.

The square root of 135591 is about 368.2268322651. The cubic root of 135591 is about 51.3740283736.

The spelling of 135591 in words is "one hundred thirty-five thousand, five hundred ninety-one".