138155393 has 2 divisors, whose sum is σ = 138155394. Its totient is φ = 138155392.

The previous prime is 138155389. The next prime is 138155401. The reversal of 138155393 is 393551831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 107163904 + 30991489 = 10352^2 + 5567^2 .

It is a cyclic number.

It is not a de Polignac number, because 138155393 - 2² = 138155389 is a prime.

It is a super-2 number, since 2×138155393² = 38173825229968898, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (138155293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69077696 + 69077697.

It is an arithmetic number, because the mean of its divisors is an integer number (69077697).

Almost surely, 2^138155393 is an apocalyptic number.

It is an amenable number.

138155393 is a deficient number, since it is larger than the sum of its proper divisors (1).

138155393 is an equidigital number, since it uses as much as digits as its factorization.

138155393 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48600, while the sum is 38.

The square root of 138155393 is about 11753.9522289313. The cubic root of 138155393 is about 516.9588178209.

The spelling of 138155393 in words is "one hundred thirty-eight million, one hundred fifty-five thousand, three hundred ninety-three".