138122509 has 4 divisors (see below), whose sum is σ = 157854304. Its totient is φ = 118390716.

The previous prime is 138122507. The next prime is 138122513. The reversal of 138122509 is 905221831.

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, and also an emirpimes, since its reverse is a distinct semiprime: 905221831 = 17 ⋅53248343.

It is a cyclic number.

It is not a de Polignac number, because 138122509 - 2¹ = 138122507 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 (138122507) 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 3 ways as a sum of consecutive naturals, for example, 9865887 + ... + 9865900.

It is an arithmetic number, because the mean of its divisors is an integer number (39463576).

Almost surely, 2^138122509 is an apocalyptic number.

It is an amenable number.

138122509 is a deficient number, since it is larger than the sum of its proper divisors (19731795).

138122509 is an equidigital number, since it uses as much as digits as its factorization.

138122509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19731794.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 138122509 is about 11752.5532970500. The cubic root of 138122509 is about 516.9177987377.

The spelling of 138122509 in words is "one hundred thirty-eight million, one hundred twenty-two thousand, five hundred nine".