138834209 has 4 divisors (see below), whose sum is σ = 138881604. Its totient is φ = 138786816.

The previous prime is 138834203. The next prime is 138834217. The reversal of 138834209 is 902438831.

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 136422400 + 2411809 = 11680^2 + 1553^2 .

It is a cyclic number.

It is not a de Polignac number, because 138834209 - 2¹² = 138830113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138834203) 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, 18992 + ... + 25265.

It is an arithmetic number, because the mean of its divisors is an integer number (34720401).

Almost surely, 2^138834209 is an apocalyptic number.

It is an amenable number.

138834209 is a deficient number, since it is larger than the sum of its proper divisors (47395).

138834209 is an equidigital number, since it uses as much as digits as its factorization.

138834209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47394.

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 138834209 is about 11782.7929201866. The cubic root of 138834209 is about 517.8041141537.

The spelling of 138834209 in words is "one hundred thirty-eight million, eight hundred thirty-four thousand, two hundred nine".