138148666 has 4 divisors (see below), whose sum is σ = 207223002. Its totient is φ = 69074332.

The previous prime is 138148607. The next prime is 138148667. The reversal of 138148666 is 666841831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666841831 = 3917 ⋅170243.

It can be written as a sum of positive squares in only one way, i.e., 119443041 + 18705625 = 10929^2 + 4325^2 .

It is not an unprimeable number, because it can be changed into a prime (138148667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34537165 + ... + 34537168.

Almost surely, 2^138148666 is an apocalyptic number.

138148666 is a deficient number, since it is larger than the sum of its proper divisors (69074336).

138148666 is an equidigital number, since it uses as much as digits as its factorization.

138148666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69074335.

The product of its digits is 165888, while the sum is 43.

The square root of 138148666 is about 11753.6660663812. Note that the first 3 decimals coincide. The cubic root of 138148666 is about 516.9504271763.

The spelling of 138148666 in words is "one hundred thirty-eight million, one hundred forty-eight thousand, six hundred sixty-six".