138877217 has 2 divisors, whose sum is σ = 138877218. Its totient is φ = 138877216.

The previous prime is 138877187. The next prime is 138877223. The reversal of 138877217 is 712778831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 95961616 + 42915601 = 9796^2 + 6551^2 .

It is a cyclic number.

It is not a de Polignac number, because 138877217 - 2¹² = 138873121 is a prime.

It is not a weakly prime, because it can be changed into another prime (138877237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69438608 + 69438609.

It is an arithmetic number, because the mean of its divisors is an integer number (69438609).

Almost surely, 2^138877217 is an apocalyptic number.

It is an amenable number.

138877217 is a deficient number, since it is larger than the sum of its proper divisors (1).

138877217 is an equidigital number, since it uses as much as digits as its factorization.

138877217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 131712, while the sum is 44.

The square root of 138877217 is about 11784.6178130646. The cubic root of 138877217 is about 517.8575770102.

The spelling of 138877217 in words is "one hundred thirty-eight million, eight hundred seventy-seven thousand, two hundred seventeen".