133640209 has 4 divisors (see below), whose sum is σ = 135250416. Its totient is φ = 132030004.

The previous prime is 133640201. The next prime is 133640219. The reversal of 133640209 is 902046331.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 133640209 - 2³ = 133640201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133640201) 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, 804979 + ... + 805144.

It is an arithmetic number, because the mean of its divisors is an integer number (33812604).

Almost surely, 2^133640209 is an apocalyptic number.

It is an amenable number.

133640209 is a deficient number, since it is larger than the sum of its proper divisors (1610207).

133640209 is an equidigital number, since it uses as much as digits as its factorization.

133640209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1610206.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 133640209 is about 11560.2858528671. The cubic root of 133640209 is about 511.2645908203.

The spelling of 133640209 in words is "one hundred thirty-three million, six hundred forty thousand, two hundred nine".