138670909 has 16 divisors (see below), whose sum is σ = 151803568. Its totient is φ = 125908992.

The previous prime is 138670891. The next prime is 138670937. The reversal of 138670909 is 909076831.

It can be written as a sum of positive squares in 8 ways, for example, as 13118884 + 125552025 = 3622^2 + 11205^2 .

It is a cyclic number.

It is not a de Polignac number, because 138670909 - 2⁵ = 138670877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138670109) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 349099 + ... + 349495.

It is an arithmetic number, because the mean of its divisors is an integer number (9487723).

Almost surely, 2^138670909 is an apocalyptic number.

It is an amenable number.

138670909 is a deficient number, since it is larger than the sum of its proper divisors (13132659).

138670909 is a wasteful number, since it uses less digits than its factorization.

138670909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 138670909 is about 11775.8612848488. The cubic root of 138670909 is about 517.6010167881.

The spelling of 138670909 in words is "one hundred thirty-eight million, six hundred seventy thousand, nine hundred nine".