138638387 has 2 divisors, whose sum is σ = 138638388. Its totient is φ = 138638386.

The previous prime is 138638359. The next prime is 138638389. The reversal of 138638387 is 783836831.

It is a strong prime.

It is an emirp because it is prime and its reverse (783836831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138638387 - 2²² = 134444083 is a prime.

Together with 138638389, 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 (138638389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69319193 + 69319194.

It is an arithmetic number, because the mean of its divisors is an integer number (69319194).

Almost surely, 2^138638387 is an apocalyptic number.

138638387 is a deficient number, since it is larger than the sum of its proper divisors (1).

138638387 is an equidigital number, since it uses as much as digits as its factorization.

138638387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580608, while the sum is 47.

The square root of 138638387 is about 11774.4803282353. The cubic root of 138638387 is about 517.5605499098.

The spelling of 138638387 in words is "one hundred thirty-eight million, six hundred thirty-eight thousand, three hundred eighty-seven".