7878778769 has 2 divisors, whose sum is σ = 7878778770. Its totient is φ = 7878778768.

The previous prime is 7878778751. The next prime is 7878778813. The reversal of 7878778769 is 9678778787.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4367623744 + 3511155025 = 66088^2 + 59255^2 .

It is a cyclic number.

It is not a de Polignac number, because 7878778769 - 2⁸ = 7878778513 is a prime.

It is a super-2 number, since 2×7878778769² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 7878778696 and 7878778705.

It is not a weakly prime, because it can be changed into another prime (7878778729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3939389384 + 3939389385.

It is an arithmetic number, because the mean of its divisors is an integer number (3939389385).

Almost surely, 2^7878778769 is an apocalyptic number.

It is an amenable number.

7878778769 is a deficient number, since it is larger than the sum of its proper divisors (1).

7878778769 is an equidigital number, since it uses as much as digits as its factorization.

7878778769 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 464679936, while the sum is 74.

The square root of 7878778769 is about 88762.4851443446. The cubic root of 7878778769 is about 1989.8467739736.

The spelling of 7878778769 in words is "seven billion, eight hundred seventy-eight million, seven hundred seventy-eight thousand, seven hundred sixty-nine".