138552209 has 4 divisors (see below), whose sum is σ = 138592740. Its totient is φ = 138511680.

The previous prime is 138552203. The next prime is 138552217. The reversal of 138552209 is 902255831.

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 44849809 + 93702400 = 6697^2 + 9680^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138552209 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (138552203) 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, 14612 + ... + 22149.

It is an arithmetic number, because the mean of its divisors is an integer number (34648185).

Almost surely, 2^138552209 is an apocalyptic number.

It is an amenable number.

138552209 is a deficient number, since it is larger than the sum of its proper divisors (40531).

138552209 is an equidigital number, since it uses as much as digits as its factorization.

138552209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40530.

The product of its (nonzero) digits is 21600, while the sum is 35.

The square root of 138552209 is about 11770.8202348010. The cubic root of 138552209 is about 517.4532886650.

The spelling of 138552209 in words is "one hundred thirty-eight million, five hundred fifty-two thousand, two hundred nine".