78554492917 has 2 divisors, whose sum is σ = 78554492918. Its totient is φ = 78554492916.

The previous prime is 78554492909. The next prime is 78554492921. The reversal of 78554492917 is 71929445587.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44988955236 + 33565537681 = 212106^2 + 183209^2 .

It is an emirp because it is prime and its reverse (71929445587) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78554492917 - 2³ = 78554492909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78554492927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39277246458 + 39277246459.

It is an arithmetic number, because the mean of its divisors is an integer number (39277246459).

Almost surely, 2^78554492917 is an apocalyptic number.

It is an amenable number.

78554492917 is a deficient number, since it is larger than the sum of its proper divisors (1).

78554492917 is an equidigital number, since it uses as much as digits as its factorization.

78554492917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25401600, while the sum is 61.

The spelling of 78554492917 in words is "seventy-eight billion, five hundred fifty-four million, four hundred ninety-two thousand, nine hundred seventeen".