133821228 has 12 divisors (see below), whose sum is σ = 312249560. Its totient is φ = 44607072.

The previous prime is 133821227. The next prime is 133821293. The reversal of 133821228 is 822128331.

133821228 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It is a super-3 number, since 3×133821228³ (a number of 25 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 133821195 and 133821204.

It is not an unprimeable number, because it can be changed into a prime (133821223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5575873 + ... + 5575896.

Almost surely, 2^133821228 is an apocalyptic number.

It is an amenable number.

133821228 is an abundant number, since it is smaller than the sum of its proper divisors (178428332).

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

133821228 is a wasteful number, since it uses less digits than its factorization.

133821228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11151776 (or 11151774 counting only the distinct ones).

The product of its digits is 4608, while the sum is 30.

The square root of 133821228 is about 11568.1125513197. The cubic root of 133821228 is about 511.4953268904.

Subtracting from 133821228 its product of digits (4608), we obtain a triangular number (133816620 = T₁₆₃₅₉).

Adding to 133821228 its reverse (822128331), we get a palindrome (955949559).

The spelling of 133821228 in words is "one hundred thirty-three million, eight hundred twenty-one thousand, two hundred twenty-eight".