133491328 has 16 divisors (see below), whose sum is σ = 265940010. Its totient is φ = 66745600.

The previous prime is 133491313. The next prime is 133491329. The reversal of 133491328 is 823194331.

It can be written as a sum of positive squares in only one way, i.e., 86266944 + 47224384 = 9288^2 + 6872^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a junction number, because it is equal to n+sod(n) for n = 133491293 and 133491302.

It is not an unprimeable number, because it can be changed into a prime (133491329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 521323 + ... + 521578.

Almost surely, 2^133491328 is an apocalyptic number.

It is an amenable number.

133491328 is a deficient number, since it is larger than the sum of its proper divisors (132448682).

133491328 is an equidigital number, since it uses as much as digits as its factorization.

133491328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1042915 (or 1042903 counting only the distinct ones).

The product of its digits is 15552, while the sum is 34.

The square root of 133491328 is about 11553.8447280548. The cubic root of 133491328 is about 511.0746632834.

The spelling of 133491328 in words is "one hundred thirty-three million, four hundred ninety-one thousand, three hundred twenty-eight".