138605287 has 2 divisors, whose sum is σ = 138605288. Its totient is φ = 138605286.

The previous prime is 138605279. The next prime is 138605377. The reversal of 138605287 is 782506831.

138605287 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is an emirp because it is prime and its reverse (782506831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138605287 - 2³ = 138605279 is a prime.

It is a super-2 number, since 2×138605287² = 38422851168704738, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138615287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69302643 + 69302644.

It is an arithmetic number, because the mean of its divisors is an integer number (69302644).

Almost surely, 2^138605287 is an apocalyptic number.

138605287 is a deficient number, since it is larger than the sum of its proper divisors (1).

138605287 is an equidigital number, since it uses as much as digits as its factorization.

138605287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 40.

The square root of 138605287 is about 11773.0746621263. The cubic root of 138605287 is about 517.5193573317.

The spelling of 138605287 in words is "one hundred thirty-eight million, six hundred five thousand, two hundred eighty-seven".