78816169 has 2 divisors, whose sum is σ = 78816170. Its totient is φ = 78816168.

The previous prime is 78816137. The next prime is 78816181. The reversal of 78816169 is 96161887.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49168144 + 29648025 = 7012^2 + 5445^2 .

It is an emirp because it is prime and its reverse (96161887) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78816169 - 2⁵ = 78816137 is a prime.

It is a super-2 number, since 2×78816169² = 12423976991673122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78816109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39408084 + 39408085.

It is an arithmetic number, because the mean of its divisors is an integer number (39408085).

Almost surely, 2^78816169 is an apocalyptic number.

It is an amenable number.

78816169 is a deficient number, since it is larger than the sum of its proper divisors (1).

78816169 is an equidigital number, since it uses as much as digits as its factorization.

78816169 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 46.

The square root of 78816169 is about 8877.8470926233. The cubic root of 78816169 is about 428.7509616436.

The spelling of 78816169 in words is "seventy-eight million, eight hundred sixteen thousand, one hundred sixty-nine".