135666 has 12 divisors (see below), whose sum is σ = 293982. Its totient is φ = 45216.

The previous prime is 135661. The next prime is 135671. The reversal of 135666 is 666531.

It is an interprime number because it is at equal distance from previous prime (135661) and next prime (135671).

It can be written as a sum of positive squares in only one way, i.e., 119025 + 16641 = 345^2 + 129^2 .

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a plaindrome in base 10 and base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 135666.

It is not an unprimeable number, because it can be changed into a prime (135661) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3751 + ... + 3786.

2¹³⁵⁶⁶⁶ is an apocalyptic number.

135666 is an abundant number, since it is smaller than the sum of its proper divisors (158316).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

135666 is a wasteful number, since it uses less digits than its factorization.

135666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7545 (or 7542 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 135666 is about 368.3286575872. The cubic root of 135666 is about 51.3834988692.

The spelling of 135666 in words is "one hundred thirty-five thousand, six hundred sixty-six".