135961 has 4 divisors (see below), whose sum is σ = 155392. Its totient is φ = 116532.

The previous prime is 135937. The next prime is 135977. The reversal of 135961 is 169531.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 135961 - 2⁵ = 135929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135911) 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, 9705 + ... + 9718.

It is an arithmetic number, because the mean of its divisors is an integer number (38848).

2¹³⁵⁹⁶¹ is an apocalyptic number.

It is an amenable number.

135961 is a deficient number, since it is larger than the sum of its proper divisors (19431).

135961 is an equidigital number, since it uses as much as digits as its factorization.

135961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19430.

The product of its digits is 810, while the sum is 25.

The square root of 135961 is about 368.7288977013. The cubic root of 135961 is about 51.4207156578.

The spelling of 135961 in words is "one hundred thirty-five thousand, nine hundred sixty-one".