138666277 has 2 divisors, whose sum is σ = 138666278. Its totient is φ = 138666276.

The previous prime is 138666257. The next prime is 138666289. The reversal of 138666277 is 772666831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137030436 + 1635841 = 11706^2 + 1279^2 .

It is an emirp because it is prime and its reverse (772666831) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138666277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138666217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69333138 + 69333139.

It is an arithmetic number, because the mean of its divisors is an integer number (69333139).

Almost surely, 2^138666277 is an apocalyptic number.

It is an amenable number.

138666277 is a deficient number, since it is larger than the sum of its proper divisors (1).

138666277 is an equidigital number, since it uses as much as digits as its factorization.

138666277 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 508032, while the sum is 46.

The square root of 138666277 is about 11775.6646096940. The cubic root of 138666277 is about 517.5952536120.

The spelling of 138666277 in words is "one hundred thirty-eight million, six hundred sixty-six thousand, two hundred seventy-seven".