138708709 has 4 divisors (see below), whose sum is σ = 138733504. Its totient is φ = 138683916.

The previous prime is 138708677. The next prime is 138708733. The reversal of 138708709 is 907807831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 138708709 - 2⁵ = 138708677 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 (138708749) 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, 394 + ... + 16660.

It is an arithmetic number, because the mean of its divisors is an integer number (34683376).

Almost surely, 2^138708709 is an apocalyptic number.

It is an amenable number.

138708709 is a deficient number, since it is larger than the sum of its proper divisors (24795).

138708709 is an equidigital number, since it uses as much as digits as its factorization.

138708709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24794.

The product of its (nonzero) digits is 84672, while the sum is 43.

The square root of 138708709 is about 11777.4661536342. The cubic root of 138708709 is about 517.6480430921.

The spelling of 138708709 in words is "one hundred thirty-eight million, seven hundred eight thousand, seven hundred nine".