138255809 has 2 divisors, whose sum is σ = 138255810. Its totient is φ = 138255808.

The previous prime is 138255797. The next prime is 138255823. The reversal of 138255809 is 908552831.

138255809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72726784 + 65529025 = 8528^2 + 8095^2 .

It is a cyclic number.

It is not a de Polignac number, because 138255809 - 2²⁰ = 137207233 is a prime.

It is a super-2 number, since 2×138255809² = 38229337444488962, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (138255869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69127904 + 69127905.

It is an arithmetic number, because the mean of its divisors is an integer number (69127905).

Almost surely, 2^138255809 is an apocalyptic number.

It is an amenable number.

138255809 is a deficient number, since it is larger than the sum of its proper divisors (1).

138255809 is an equidigital number, since it uses as much as digits as its factorization.

138255809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 86400, while the sum is 41.

The square root of 138255809 is about 11758.2230375172. The cubic root of 138255809 is about 517.0840351908.

The spelling of 138255809 in words is "one hundred thirty-eight million, two hundred fifty-five thousand, eight hundred nine".