133428 has 12 divisors (see below), whose sum is σ = 311360. Its totient is φ = 44472.

The previous prime is 133417. The next prime is 133439. The reversal of 133428 is 824331.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (133417) and next prime (133439).

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

133428 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5548 + ... + 5571.

2¹³³⁴²⁸ is an apocalyptic number.

It is an amenable number.

133428 is an abundant number, since it is smaller than the sum of its proper divisors (177932).

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

133428 is a wasteful number, since it uses less digits than its factorization.

133428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11126 (or 11124 counting only the distinct ones).

The product of its digits is 576, while the sum is 21.

The square root of 133428 is about 365.2779763413. The cubic root of 133428 is about 51.0993832925.

Adding to 133428 its reverse (824331), we get a palindrome (957759).

It can be divided in two parts, 133 and 428, that added together give a triangular number (561 = T₃₃).

The spelling of 133428 in words is "one hundred thirty-three thousand, four hundred twenty-eight".