78558542173 has 2 divisors, whose sum is σ = 78558542174. Its totient is φ = 78558542172.

The previous prime is 78558542143. The next prime is 78558542177. The reversal of 78558542173 is 37124585587.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78233208804 + 325333369 = 279702^2 + 18037^2 .

It is a cyclic number.

It is not a de Polignac number, because 78558542173 - 2⁵ = 78558542141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78558542177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39279271086 + 39279271087.

It is an arithmetic number, because the mean of its divisors is an integer number (39279271087).

Almost surely, 2^78558542173 is an apocalyptic number.

It is an amenable number.

78558542173 is a deficient number, since it is larger than the sum of its proper divisors (1).

78558542173 is an equidigital number, since it uses as much as digits as its factorization.

78558542173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9408000, while the sum is 55.

The spelling of 78558542173 in words is "seventy-eight billion, five hundred fifty-eight million, five hundred forty-two thousand, one hundred seventy-three".