78796221712891 has 2 divisors, whose sum is σ = 78796221712892. Its totient is φ = 78796221712890.

The previous prime is 78796221712889. The next prime is 78796221712909. The reversal of 78796221712891 is 19821712269787.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78796221712891 - 2¹ = 78796221712889 is a prime.

Together with 78796221712889, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 78796221712891.

It is not a weakly prime, because it can be changed into another prime (78796221712811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39398110856445 + 39398110856446.

It is an arithmetic number, because the mean of its divisors is an integer number (39398110856446).

Almost surely, 2^{78796221712891} is an apocalyptic number.

78796221712891 is a deficient number, since it is larger than the sum of its proper divisors (1).

78796221712891 is an equidigital number, since it uses as much as digits as its factorization.

78796221712891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 85349376, while the sum is 70.

The spelling of 78796221712891 in words is "seventy-eight trillion, seven hundred ninety-six billion, two hundred twenty-one million, seven hundred twelve thousand, eight hundred ninety-one".