138609847 has 4 divisors (see below), whose sum is σ = 138633880. Its totient is φ = 138585816.

The previous prime is 138609811. The next prime is 138609851. The reversal of 138609847 is 748906831.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a 3-Lehmer number, since φ(138609847) divides (138609847-1)³.

It is a cyclic number.

It is not a de Polignac number, because 138609847 - 2⁷ = 138609719 is a prime.

It is a deceptive number, since it divides R_138609846.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 138609797 and 138609806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138609547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2404 + ... + 16822.

It is an arithmetic number, because the mean of its divisors is an integer number (34658470).

Almost surely, 2^138609847 is an apocalyptic number.

138609847 is the 9613-rd pentagonal number.

138609847 is a deficient number, since it is larger than the sum of its proper divisors (24033).

138609847 is an equidigital number, since it uses as much as digits as its factorization.

138609847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24032.

The product of its (nonzero) digits is 290304, while the sum is 46.

The square root of 138609847 is about 11773.2683227726. The cubic root of 138609847 is about 517.5250325900.

The spelling of 138609847 in words is "one hundred thirty-eight million, six hundred nine thousand, eight hundred forty-seven".