138658609 has 8 divisors (see below), whose sum is σ = 140763392. Its totient is φ = 136559520.

The previous prime is 138658603. The next prime is 138658621. The reversal of 138658609 is 906856831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 138658609 - 2⁹ = 138658097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138658603) 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 7 ways as a sum of consecutive naturals, for example, 89092 + ... + 90634.

It is an arithmetic number, because the mean of its divisors is an integer number (17595424).

Almost surely, 2^138658609 is an apocalyptic number.

It is an amenable number.

138658609 is a deficient number, since it is larger than the sum of its proper divisors (2104783).

138658609 is a wasteful number, since it uses less digits than its factorization.

138658609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2847.

The product of its (nonzero) digits is 311040, while the sum is 46.

The square root of 138658609 is about 11775.3390184742. The cubic root of 138658609 is about 517.5857127353.

It can be divided in two parts, 1386 and 58609, that added together give a palindrome (59995).

The spelling of 138658609 in words is "one hundred thirty-eight million, six hundred fifty-eight thousand, six hundred nine".