78454768891 has 2 divisors, whose sum is σ = 78454768892. Its totient is φ = 78454768890.

The previous prime is 78454768867. The next prime is 78454768913. The reversal of 78454768891 is 19886745487.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78454768891 is a prime.

It is not a weakly prime, because it can be changed into another prime (78454768841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39227384445 + 39227384446.

It is an arithmetic number, because the mean of its divisors is an integer number (39227384446).

Almost surely, 2^78454768891 is an apocalyptic number.

78454768891 is a deficient number, since it is larger than the sum of its proper divisors (1).

78454768891 is an equidigital number, since it uses as much as digits as its factorization.

78454768891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108380160, while the sum is 67.

The spelling of 78454768891 in words is "seventy-eight billion, four hundred fifty-four million, seven hundred sixty-eight thousand, eight hundred ninety-one".