133805209 has 4 divisors (see below), whose sum is σ = 137421604. Its totient is φ = 130188816.

The previous prime is 133805183. The next prime is 133805257. The reversal of 133805209 is 902508331.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 54096025 + 79709184 = 7355^2 + 8928^2 .

It is a cyclic number.

It is not a de Polignac number, because 133805209 - 2⁷ = 133805081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133805299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1808142 + ... + 1808215.

It is an arithmetic number, because the mean of its divisors is an integer number (34355401).

Almost surely, 2^133805209 is an apocalyptic number.

It is an amenable number.

133805209 is a deficient number, since it is larger than the sum of its proper divisors (3616395).

133805209 is an equidigital number, since it uses as much as digits as its factorization.

133805209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3616394.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 133805209 is about 11567.4201531716. The cubic root of 133805209 is about 511.4749166493.

The spelling of 133805209 in words is "one hundred thirty-three million, eight hundred five thousand, two hundred nine".