78320791 has 2 divisors, whose sum is σ = 78320792. Its totient is φ = 78320790.

The previous prime is 78320779. The next prime is 78320821. The reversal of 78320791 is 19702387.

It is a weak prime.

It is an emirp because it is prime and its reverse (19702387) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78320791 is a prime.

It is a super-2 number, since 2×78320791² = 12268292605731362, 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 78320791.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78320731) 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, 39160395 + 39160396.

It is an arithmetic number, because the mean of its divisors is an integer number (39160396).

Almost surely, 2^78320791 is an apocalyptic number.

78320791 is a deficient number, since it is larger than the sum of its proper divisors (1).

78320791 is an equidigital number, since it uses as much as digits as its factorization.

78320791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 78320791 is about 8849.9034458010. The cubic root of 78320791 is about 427.8508065172.

The spelling of 78320791 in words is "seventy-eight million, three hundred twenty thousand, seven hundred ninety-one".