78451309 has 2 divisors, whose sum is σ = 78451310. Its totient is φ = 78451308.

The previous prime is 78451301. The next prime is 78451337. The reversal of 78451309 is 90315487.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44555625 + 33895684 = 6675^2 + 5822^2 .

It is an emirp because it is prime and its reverse (90315487) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78451309 - 2³ = 78451301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78451301) 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, 39225654 + 39225655.

It is an arithmetic number, because the mean of its divisors is an integer number (39225655).

Almost surely, 2^78451309 is an apocalyptic number.

It is an amenable number.

78451309 is a deficient number, since it is larger than the sum of its proper divisors (1).

78451309 is an equidigital number, since it uses as much as digits as its factorization.

78451309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 78451309 is about 8857.2743550146. The cubic root of 78451309 is about 428.0883391912.

The spelling of 78451309 in words is "seventy-eight million, four hundred fifty-one thousand, three hundred nine".