138877666 has 4 divisors (see below), whose sum is σ = 208316502. Its totient is φ = 69438832.

The previous prime is 138877643. The next prime is 138877679. The reversal of 138877666 is 666778831.

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

It can be written as a sum of positive squares in only one way, i.e., 124657225 + 14220441 = 11165^2 + 3771^2 .

It is a super-2 number, since 2×138877666² = 38574012227215112, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34719415 + ... + 34719418.

Almost surely, 2^138877666 is an apocalyptic number.

138877666 is a deficient number, since it is larger than the sum of its proper divisors (69438836).

138877666 is an equidigital number, since it uses as much as digits as its factorization.

138877666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69438835.

The product of its digits is 2032128, while the sum is 52.

The square root of 138877666 is about 11784.6368633064. The cubic root of 138877666 is about 517.8581350998.

The spelling of 138877666 in words is "one hundred thirty-eight million, eight hundred seventy-seven thousand, six hundred sixty-six".