133668 has 36 divisors (see below), whose sum is σ = 349440. Its totient is φ = 43056.

The previous prime is 133657. The next prime is 133669. The reversal of 133668 is 866331.

It is a tau number, because it is divible by the number of its divisors (36).

It is a plaindrome in base 10.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133669) by changing a digit.

133668 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1653 + ... + 1731.

2¹³³⁶⁶⁸ is an apocalyptic number.

133668 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 133668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (174720).

133668 is an abundant number, since it is smaller than the sum of its proper divisors (215772).

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

133668 is a wasteful number, since it uses less digits than its factorization.

133668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136 (or 131 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 133668 is about 365.6063456780. The cubic root of 133668 is about 51.1300028182.

Adding to 133668 its reverse (866331), we get a palindrome (999999).

The spelling of 133668 in words is "one hundred thirty-three thousand, six hundred sixty-eight".