78494309 has 2 divisors, whose sum is σ = 78494310. Its totient is φ = 78494308.

The previous prime is 78494303. The next prime is 78494341. The reversal of 78494309 is 90349487.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43270084 + 35224225 = 6578^2 + 5935^2 .

It is an emirp because it is prime and its reverse (90349487) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78494309 - 2⁴ = 78494293 is a prime.

It is a super-2 number, since 2×78494309² = 12322713090774962, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78494309.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78494303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39247154 + 39247155.

It is an arithmetic number, because the mean of its divisors is an integer number (39247155).

Almost surely, 2^78494309 is an apocalyptic number.

It is an amenable number.

78494309 is a deficient number, since it is larger than the sum of its proper divisors (1).

78494309 is an equidigital number, since it uses as much as digits as its factorization.

78494309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 78494309 is about 8859.7014058037. The cubic root of 78494309 is about 428.1665381687.

The spelling of 78494309 in words is "seventy-eight million, four hundred ninety-four thousand, three hundred nine".