138172009 has 16 divisors (see below), whose sum is σ = 150857280. Its totient is φ = 126109440.

The previous prime is 138171973. The next prime is 138172019. The reversal of 138172009 is 900271831.

It is not a de Polignac number, because 138172009 - 2⁷ = 138171881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138172019) 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 15 ways as a sum of consecutive naturals, for example, 63589 + ... + 65725.

It is an arithmetic number, because the mean of its divisors is an integer number (9428580).

Almost surely, 2^138172009 is an apocalyptic number.

138172009 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

138172009 is a deficient number, since it is larger than the sum of its proper divisors (12685271).

138172009 is a wasteful number, since it uses less digits than its factorization.

138172009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2280.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 138172009 is about 11754.6590337619. The cubic root of 138172009 is about 516.9795419326.

The spelling of 138172009 in words is "one hundred thirty-eight million, one hundred seventy-two thousand, nine".