138668977 has 2 divisors, whose sum is σ = 138668978. Its totient is φ = 138668976.

The previous prime is 138668953. The next prime is 138668993. The reversal of 138668977 is 779866831.

138668977 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135396496 + 3272481 = 11636^2 + 1809^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138668977 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (138668927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69334488 + 69334489.

It is an arithmetic number, because the mean of its divisors is an integer number (69334489).

Almost surely, 2^138668977 is an apocalyptic number.

It is an amenable number.

138668977 is a deficient number, since it is larger than the sum of its proper divisors (1).

138668977 is an equidigital number, since it uses as much as digits as its factorization.

138668977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3048192, while the sum is 55.

The square root of 138668977 is about 11775.7792523467. The cubic root of 138668977 is about 517.5986129919.

The spelling of 138668977 in words is "one hundred thirty-eight million, six hundred sixty-eight thousand, nine hundred seventy-seven".