138656789 has 2 divisors, whose sum is σ = 138656790. Its totient is φ = 138656788.

The previous prime is 138656773. The next prime is 138656827. The reversal of 138656789 is 987656831.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72965764 + 65691025 = 8542^2 + 8105^2 .

It is a cyclic number.

It is not a de Polignac number, because 138656789 - 2⁴ = 138656773 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138656789.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138656759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69328394 + 69328395.

It is an arithmetic number, because the mean of its divisors is an integer number (69328395).

Almost surely, 2^138656789 is an apocalyptic number.

It is an amenable number.

138656789 is a deficient number, since it is larger than the sum of its proper divisors (1).

138656789 is an equidigital number, since it uses as much as digits as its factorization.

138656789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2177280, while the sum is 53.

The square root of 138656789 is about 11775.2617380677. The cubic root of 138656789 is about 517.5834481563.

The spelling of 138656789 in words is "one hundred thirty-eight million, six hundred fifty-six thousand, seven hundred eighty-nine".