78937009 has 2 divisors, whose sum is σ = 78937010. Its totient is φ = 78937008.

The previous prime is 78936973. The next prime is 78937057. The reversal of 78937009 is 90073987.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60403984 + 18533025 = 7772^2 + 4305^2 .

It is an emirp because it is prime and its reverse (90073987) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78937009 - 2⁹ = 78936497 is a prime.

It is not a weakly prime, because it can be changed into another prime (78937099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39468504 + 39468505.

It is an arithmetic number, because the mean of its divisors is an integer number (39468505).

Almost surely, 2^78937009 is an apocalyptic number.

It is an amenable number.

78937009 is a deficient number, since it is larger than the sum of its proper divisors (1).

78937009 is an equidigital number, since it uses as much as digits as its factorization.

78937009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 95256, while the sum is 43.

The square root of 78937009 is about 8884.6501900750. The cubic root of 78937009 is about 428.9699683572.

The spelling of 78937009 in words is "seventy-eight million, nine hundred thirty-seven thousand, nine".