135631 has 4 divisors (see below), whose sum is σ = 141552. Its totient is φ = 129712.

The previous prime is 135623. The next prime is 135637. The reversal of 135631 is 136531.

135631 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 135631 - 2³ = 135623 is a prime.

It is a super-3 number, since 3×135631³ = 7485109294333773, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

135631 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 135599 and 135608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135637) 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, 2926 + ... + 2971.

It is an arithmetic number, because the mean of its divisors is an integer number (35388).

2¹³⁵⁶³¹ is an apocalyptic number.

135631 is a deficient number, since it is larger than the sum of its proper divisors (5921).

135631 is an equidigital number, since it uses as much as digits as its factorization.

135631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5920.

The product of its digits is 270, while the sum is 19.

The square root of 135631 is about 368.2811426071. The cubic root of 135631 is about 51.3790797391.

Subtracting 135631 from its reverse (136531), we obtain a square (900 = 30²).

The spelling of 135631 in words is "one hundred thirty-five thousand, six hundred thirty-one".