136440209 has 6 divisors (see below), whose sum is σ = 142630866. Its totient is φ = 130507520.

The previous prime is 136440191. The next prime is 136440211. The reversal of 136440209 is 902044631.

It can be written as a sum of positive squares in only one way, i.e., 132250000 + 4190209 = 11500^2 + 2047^2 .

It is a de Polignac number, because none of the positive numbers 2^k-136440209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (136445209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 128432 + ... + 129489.

It is an arithmetic number, because the mean of its divisors is an integer number (23771811).

Almost surely, 2^136440209 is an apocalyptic number.

It is an amenable number.

136440209 is a deficient number, since it is larger than the sum of its proper divisors (6190657).

136440209 is an equidigital number, since it uses as much as digits as its factorization.

136440209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257967 (or 257944 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 136440209 is about 11680.7623466964. The cubic root of 136440209 is about 514.8105741274.

The spelling of 136440209 in words is "one hundred thirty-six million, four hundred forty thousand, two hundred nine".