78087173 has 2 divisors, whose sum is σ = 78087174. Its totient is φ = 78087172.

The previous prime is 78087161. The next prime is 78087193. The reversal of 78087173 is 37178087.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75724804 + 2362369 = 8702^2 + 1537^2 .

It is a cyclic number.

It is not a de Polignac number, because 78087173 - 2¹⁰ = 78086149 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78087173.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78087193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39043586 + 39043587.

It is an arithmetic number, because the mean of its divisors is an integer number (39043587).

Almost surely, 2^78087173 is an apocalyptic number.

It is an amenable number.

78087173 is a deficient number, since it is larger than the sum of its proper divisors (1).

78087173 is an equidigital number, since it uses as much as digits as its factorization.

78087173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 65856, while the sum is 41.

The square root of 78087173 is about 8836.6946874949. The cubic root of 78087173 is about 427.4249800532.

The spelling of 78087173 in words is "seventy-eight million, eighty-seven thousand, one hundred seventy-three".