138320209 has 4 divisors (see below), whose sum is σ = 145600240. Its totient is φ = 131040180.

The previous prime is 138320197. The next prime is 138320213. The reversal of 138320209 is 902023831.

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 138320209 - 2⁹ = 138319697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138320009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3639987 + ... + 3640024.

It is an arithmetic number, because the mean of its divisors is an integer number (36400060).

Almost surely, 2^138320209 is an apocalyptic number.

138320209 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

138320209 is a deficient number, since it is larger than the sum of its proper divisors (7280031).

138320209 is an equidigital number, since it uses as much as digits as its factorization.

138320209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7280030.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 138320209 is about 11760.9612277228. The cubic root of 138320209 is about 517.1643091964.

The spelling of 138320209 in words is "one hundred thirty-eight million, three hundred twenty thousand, two hundred nine".