138915787 has 2 divisors, whose sum is σ = 138915788. Its totient is φ = 138915786.

The previous prime is 138915779. The next prime is 138915827. The reversal of 138915787 is 787519831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138915787 - 2³ = 138915779 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138915787.

It is not a weakly prime, because it can be changed into another prime (138915487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69457893 + 69457894.

It is an arithmetic number, because the mean of its divisors is an integer number (69457894).

Almost surely, 2^138915787 is an apocalyptic number.

138915787 is a deficient number, since it is larger than the sum of its proper divisors (1).

138915787 is an equidigital number, since it uses as much as digits as its factorization.

138915787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 423360, while the sum is 49.

The square root of 138915787 is about 11786.2541547347. The cubic root of 138915787 is about 517.9055136418.

The spelling of 138915787 in words is "one hundred thirty-eight million, nine hundred fifteen thousand, seven hundred eighty-seven".