78635686849 has 2 divisors, whose sum is σ = 78635686850. Its totient is φ = 78635686848.

The previous prime is 78635686847. The next prime is 78635686853. The reversal of 78635686849 is 94868653687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74279686849 + 4356000000 = 272543^2 + 66000^2 .

It is a cyclic number.

It is not a de Polignac number, because 78635686849 - 2¹ = 78635686847 is a prime.

Together with 78635686847, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (78635686847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39317843424 + 39317843425.

It is an arithmetic number, because the mean of its divisors is an integer number (39317843425).

Almost surely, 2^78635686849 is an apocalyptic number.

It is an amenable number.

78635686849 is a deficient number, since it is larger than the sum of its proper divisors (1).

78635686849 is an equidigital number, since it uses as much as digits as its factorization.

78635686849 is an evil number, because the sum of its binary digits is even.

The product of its digits is 418037760, while the sum is 70.

The spelling of 78635686849 in words is "seventy-eight billion, six hundred thirty-five million, six hundred eighty-six thousand, eight hundred forty-nine".