133644 has 48 divisors (see below), whose sum is σ = 374528. Its totient is φ = 36288.

The previous prime is 133633. The next prime is 133649. The reversal of 133644 is 446331.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a nude number because it is divisible by every one of its digits.

It is a nialpdrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 133644.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 133644.

It is not an unprimeable number, because it can be changed into a prime (133649) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 3087 + ... + 3129.

2¹³³⁶⁴⁴ is an apocalyptic number.

133644 is a gapful number since it is divisible by the number (14) 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 133644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (187264).

133644 is an abundant number, since it is smaller than the sum of its proper divisors (240884).

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

133644 is a wasteful number, since it uses less digits than its factorization.

133644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94 (or 92 counting only the distinct ones).

The product of its digits is 864, while the sum is 21.

The square root of 133644 is about 365.5735220171. The cubic root of 133644 is about 51.1269425158.

Adding to 133644 its reverse (446331), we get a palindrome (579975).

It can be divided in two parts, 133 and 644, that added together give a palindrome (777).

The spelling of 133644 in words is "one hundred thirty-three thousand, six hundred forty-four".