138764687 has 4 divisors (see below), whose sum is σ = 138788256. Its totient is φ = 138741120.

The previous prime is 138764677. The next prime is 138764699. The reversal of 138764687 is 786467831.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 786467831 = 79 ⋅9955289.

It is a cyclic number.

It is not a de Polignac number, because 138764687 - 2¹⁰ = 138763663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138764677) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5423 + ... + 17519.

It is an arithmetic number, because the mean of its divisors is an integer number (34697064).

Almost surely, 2^138764687 is an apocalyptic number.

138764687 is a deficient number, since it is larger than the sum of its proper divisors (23569).

138764687 is a wasteful number, since it uses less digits than its factorization.

138764687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23568.

The product of its digits is 1354752, while the sum is 50.

The square root of 138764687 is about 11779.8424013227. The cubic root of 138764687 is about 517.7176686290.

The spelling of 138764687 in words is "one hundred thirty-eight million, seven hundred sixty-four thousand, six hundred eighty-seven".