135561 has 8 divisors (see below), whose sum is σ = 183520. Its totient is φ = 88992.

The previous prime is 135559. The next prime is 135571. The reversal of 135561 is 165531.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 135561 - 2¹ = 135559 is a prime.

It is a Duffinian number.

135561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (135511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91 + ... + 528.

It is an arithmetic number, because the mean of its divisors is an integer number (22940).

2¹³⁵⁵⁶¹ is an apocalyptic number.

It is an amenable number.

135561 is a deficient number, since it is larger than the sum of its proper divisors (47959).

135561 is an equidigital number, since it uses as much as digits as its factorization.

135561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 695.

The product of its digits is 450, while the sum is 21.

The square root of 135561 is about 368.1860942513. The cubic root of 135561 is about 51.3702391975.

It can be divided in two parts, 135 and 561, that added together give a palindrome (696).

The spelling of 135561 in words is "one hundred thirty-five thousand, five hundred sixty-one".