138518557 has 2 divisors, whose sum is σ = 138518558. Its totient is φ = 138518556.

The previous prime is 138518543. The next prime is 138518561. The reversal of 138518557 is 755815831.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 112975641 + 25542916 = 10629^2 + 5054^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138518557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138518537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69259278 + 69259279.

It is an arithmetic number, because the mean of its divisors is an integer number (69259279).

Almost surely, 2^138518557 is an apocalyptic number.

It is an amenable number.

138518557 is a deficient number, since it is larger than the sum of its proper divisors (1).

138518557 is an equidigital number, since it uses as much as digits as its factorization.

138518557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 168000, while the sum is 43.

The square root of 138518557 is about 11769.3906809146. The cubic root of 138518557 is about 517.4113917074.

The spelling of 138518557 in words is "one hundred thirty-eight million, five hundred eighteen thousand, five hundred fifty-seven".