138009781987 has 12 divisors (see below), whose sum is σ = 175136718456. Its totient is φ = 107540089440.

The previous prime is 138009781979. The next prime is 138009781997. The reversal of 138009781987 is 789187900831.

It is not a de Polignac number, because 138009781987 - 2³ = 138009781979 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138009781997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 128023378 + ... + 128024455.

It is an arithmetic number, because the mean of its divisors is an integer number (14594726538).

Almost surely, 2^138009781987 is an apocalyptic number.

138009781987 is a deficient number, since it is larger than the sum of its proper divisors (37126936469).

138009781987 is a wasteful number, since it uses less digits than its factorization.

138009781987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256047858 (or 256047851 counting only the distinct ones).

The product of its (nonzero) digits is 6096384, while the sum is 61.

The spelling of 138009781987 in words is "one hundred thirty-eight billion, nine million, seven hundred eighty-one thousand, nine hundred eighty-seven".