136681 has 4 divisors (see below), whose sum is σ = 138112. Its totient is φ = 135252.

The previous prime is 136657. The next prime is 136691. The reversal of 136681 is 186631.

136681 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, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 186631 = 193 ⋅967.

It is a cyclic number.

It is not a de Polignac number, because 136681 - 2⁵ = 136649 is a prime.

It is a super-2 number, since 2×136681² = 37363391522, which contains 22 as substring.

It is a Duffinian number.

136681 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (136601) 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, 561 + ... + 766.

It is an arithmetic number, because the mean of its divisors is an integer number (34528).

2¹³⁶⁶⁸¹ is an apocalyptic number.

It is an amenable number.

136681 is a deficient number, since it is larger than the sum of its proper divisors (1431).

136681 is a wasteful number, since it uses less digits than its factorization.

136681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1430.

The product of its digits is 864, while the sum is 25.

The square root of 136681 is about 369.7039356025. The cubic root of 136681 is about 51.5113243705.

The spelling of 136681 in words is "one hundred thirty-six thousand, six hundred eighty-one".