135906981 has 16 divisors (see below), whose sum is σ = 217996800. Its totient is φ = 73573488.

The previous prime is 135906973. The next prime is 135907039. The reversal of 135906981 is 189609531.

It is not a de Polignac number, because 135906981 - 2³ = 135906973 is a prime.

It is a super-2 number, since 2×135906981² = 36941414969068722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135906941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 169911 + ... + 170708.

It is an arithmetic number, because the mean of its divisors is an integer number (13624800).

Almost surely, 2^135906981 is an apocalyptic number.

It is an amenable number.

135906981 is a deficient number, since it is larger than the sum of its proper divisors (82089819).

135906981 is a wasteful number, since it uses less digits than its factorization.

135906981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340648.

The product of its (nonzero) digits is 58320, while the sum is 42.

The square root of 135906981 is about 11657.9149507963. The cubic root of 135906981 is about 514.1390472529.

The spelling of 135906981 in words is "one hundred thirty-five million, nine hundred six thousand, nine hundred eighty-one".