138617989 has 2 divisors, whose sum is σ = 138617990. Its totient is φ = 138617988.

The previous prime is 138617981. The next prime is 138618023. The reversal of 138617989 is 989716831.

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., 134165889 + 4452100 = 11583^2 + 2110^2 .

It is a cyclic number.

It is not a de Polignac number, because 138617989 - 2³ = 138617981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138617981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69308994 + 69308995.

It is an arithmetic number, because the mean of its divisors is an integer number (69308995).

Almost surely, 2^138617989 is an apocalyptic number.

It is an amenable number.

138617989 is a deficient number, since it is larger than the sum of its proper divisors (1).

138617989 is an equidigital number, since it uses as much as digits as its factorization.

138617989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 653184, while the sum is 52.

The square root of 138617989 is about 11773.6141010312. The cubic root of 138617989 is about 517.5351656034.

The spelling of 138617989 in words is "one hundred thirty-eight million, six hundred seventeen thousand, nine hundred eighty-nine".