138866666 has 8 divisors (see below), whose sum is σ = 208475364. Its totient is φ = 69374880.

The previous prime is 138866641. The next prime is 138866669. The reversal of 138866666 is 666668831.

It can be written as a sum of positive squares in 2 ways, for example, as 112805641 + 26061025 = 10621^2 + 5105^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

138866666 is a modest number, since divided by 66666 gives 1388 as remainder.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (138866669) 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, 26195 + ... + 31046.

Almost surely, 2^138866666 is an apocalyptic number.

138866666 is a deficient number, since it is larger than the sum of its proper divisors (69608698).

138866666 is a wasteful number, since it uses less digits than its factorization.

138866666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58456.

The product of its digits is 1492992, while the sum is 50.

The square root of 138866666 is about 11784.1701447323. The cubic root of 138866666 is about 517.8444621793.

The spelling of 138866666 in words is "one hundred thirty-eight million, eight hundred sixty-six thousand, six hundred sixty-six".