135881 has 4 divisors (see below), whose sum is σ = 143892. Its totient is φ = 127872.

The previous prime is 135859. The next prime is 135887. The reversal of 135881 is 188531.

135881 = T₄₆ + T₄₇ + ... + T₉₆.

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

It can be written as a sum of positive squares in 2 ways, for example, as 55225 + 80656 = 235^2 + 284^2 .

It is a cyclic number.

It is not a de Polignac number, because 135881 - 2¹⁰ = 134857 is a prime.

It is a super-2 number, since 2×135881² = 36927292322, which contains 22 as substring.

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 135881.

It is not an unprimeable number, because it can be changed into a prime (135887) 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, 3980 + ... + 4013.

It is an arithmetic number, because the mean of its divisors is an integer number (35973).

2¹³⁵⁸⁸¹ is an apocalyptic number.

It is an amenable number.

135881 is a deficient number, since it is larger than the sum of its proper divisors (8011).

135881 is an equidigital number, since it uses as much as digits as its factorization.

135881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8010.

The product of its digits is 960, while the sum is 26.

The square root of 135881 is about 368.6204009547. The cubic root of 135881 is about 51.4106282937.

Subtracting 135881 from its reverse (188531), we obtain a triangular number (52650 = T₃₂₄).

The spelling of 135881 in words is "one hundred thirty-five thousand, eight hundred eighty-one".