133591021 has 4 divisors (see below), whose sum is σ = 133726012. Its totient is φ = 133456032.

The previous prime is 133591013. The next prime is 133591097. The reversal of 133591021 is 120195331.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120195331 = 59 ⋅2037209.

It can be written as a sum of positive squares in 2 ways, for example, as 88566921 + 45024100 = 9411^2 + 6710^2 .

It is a cyclic number.

It is not a de Polignac number, because 133591021 - 2³ = 133591013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133591001) 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, 66000 + ... + 67993.

It is an arithmetic number, because the mean of its divisors is an integer number (33431503).

Almost surely, 2^133591021 is an apocalyptic number.

It is an amenable number.

133591021 is a deficient number, since it is larger than the sum of its proper divisors (134991).

133591021 is an equidigital number, since it uses as much as digits as its factorization.

133591021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134990.

The product of its (nonzero) digits is 810, while the sum is 25.

The square root of 133591021 is about 11558.1582010284. The cubic root of 133591021 is about 511.2018572840.

The spelling of 133591021 in words is "one hundred thirty-three million, five hundred ninety-one thousand, twenty-one".