135661 has 2 divisors, whose sum is σ = 135662. Its totient is φ = 135660.

The previous prime is 135649. The next prime is 135671. The reversal of 135661 is 166531.

135661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 93636 + 42025 = 306^2 + 205^2 .

It is a cyclic number.

It is not a de Polignac number, because 135661 - 2⁷ = 135533 is a prime.

It is a nialpdrome in base 12.

It is a zygodrome in base 12.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67830 + 67831.

It is an arithmetic number, because the mean of its divisors is an integer number (67831).

2¹³⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

135661 is a deficient number, since it is larger than the sum of its proper divisors (1).

135661 is an equidigital number, since it uses as much as digits as its factorization.

135661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 540, while the sum is 22.

The square root of 135661 is about 368.3218701082. The cubic root of 135661 is about 51.3828676115.

The spelling of 135661 in words is "one hundred thirty-five thousand, six hundred sixty-one".