78764839 has 2 divisors, whose sum is σ = 78764840. Its totient is φ = 78764838.

The previous prime is 78764801. The next prime is 78764849. The reversal of 78764839 is 93846787.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (93846787) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78764839 - 2⁷ = 78764711 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78764849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39382419 + 39382420.

It is an arithmetic number, because the mean of its divisors is an integer number (39382420).

Almost surely, 2^78764839 is an apocalyptic number.

78764839 is a deficient number, since it is larger than the sum of its proper divisors (1).

78764839 is an equidigital number, since it uses as much as digits as its factorization.

78764839 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2032128, while the sum is 52.

The square root of 78764839 is about 8874.9557181994. The cubic root of 78764839 is about 428.6578649839.

The spelling of 78764839 in words is "seventy-eight million, seven hundred sixty-four thousand, eight hundred thirty-nine".