138149909 has 2 divisors, whose sum is σ = 138149910. Its totient is φ = 138149908.

The previous prime is 138149831. The next prime is 138149917. The reversal of 138149909 is 909941831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138133009 + 16900 = 11753^2 + 130^2 .

It is a cyclic number.

It is not a de Polignac number, because 138149909 - 2²⁰ = 137101333 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138149909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138140909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69074954 + 69074955.

It is an arithmetic number, because the mean of its divisors is an integer number (69074955).

Almost surely, 2^138149909 is an apocalyptic number.

It is an amenable number.

138149909 is a deficient number, since it is larger than the sum of its proper divisors (1).

138149909 is an equidigital number, since it uses as much as digits as its factorization.

138149909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69984, while the sum is 44.

The square root of 138149909 is about 11753.7189433813. The cubic root of 138149909 is about 516.9519776014.

The spelling of 138149909 in words is "one hundred thirty-eight million, one hundred forty-nine thousand, nine hundred nine".