138530681 has 2 divisors, whose sum is σ = 138530682. Its totient is φ = 138530680.

The previous prime is 138530669. The next prime is 138530683. The reversal of 138530681 is 186035831.

138530681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 104366656 + 34164025 = 10216^2 + 5845^2 .

It is a cyclic number.

It is not a de Polignac number, because 138530681 - 2⁶ = 138530617 is a prime.

It is a super-2 number, since 2×138530681² = 38381499156647522, which contains 22 as substring.

Together with 138530683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (138530683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69265340 + 69265341.

It is an arithmetic number, because the mean of its divisors is an integer number (69265341).

Almost surely, 2^138530681 is an apocalyptic number.

It is an amenable number.

138530681 is a deficient number, since it is larger than the sum of its proper divisors (1).

138530681 is an equidigital number, since it uses as much as digits as its factorization.

138530681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 138530681 is about 11769.9057345418. The cubic root of 138530681 is about 517.4264869477.

The spelling of 138530681 in words is "one hundred thirty-eight million, five hundred thirty thousand, six hundred eighty-one".