77938122217 has 2 divisors, whose sum is σ = 77938122218. Its totient is φ = 77938122216.

The previous prime is 77938122173. The next prime is 77938122313. The reversal of 77938122217 is 71222183977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76037511001 + 1900611216 = 275749^2 + 43596^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77938122217 is a prime.

It is not a weakly prime, because it can be changed into another prime (77938122617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38969061108 + 38969061109.

It is an arithmetic number, because the mean of its divisors is an integer number (38969061109).

Almost surely, 2^77938122217 is an apocalyptic number.

It is an amenable number.

77938122217 is a deficient number, since it is larger than the sum of its proper divisors (1).

77938122217 is an equidigital number, since it uses as much as digits as its factorization.

77938122217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 592704, while the sum is 49.

The spelling of 77938122217 in words is "seventy-seven billion, nine hundred thirty-eight million, one hundred twenty-two thousand, two hundred seventeen".