138678787 has 4 divisors (see below), whose sum is σ = 149346400. Its totient is φ = 128011176.

The previous prime is 138678781. The next prime is 138678791. The reversal of 138678787 is 787876831.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 138678787 - 2¹⁵ = 138646019 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138678781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5333787 + ... + 5333812.

It is an arithmetic number, because the mean of its divisors is an integer number (37336600).

Almost surely, 2^138678787 is an apocalyptic number.

138678787 is a deficient number, since it is larger than the sum of its proper divisors (10667613).

138678787 is a wasteful number, since it uses less digits than its factorization.

138678787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10667612.

The product of its digits is 3161088, while the sum is 55.

The square root of 138678787 is about 11776.1957779242. The cubic root of 138678787 is about 517.6108183719.

The spelling of 138678787 in words is "one hundred thirty-eight million, six hundred seventy-eight thousand, seven hundred eighty-seven".