6778393561 has 27 divisors (see below), whose sum is σ = 7502357629. Its totient is φ = 6122791808.

The previous prime is 6778393543. The next prime is 6778393571. The reversal of 6778393561 is 1653938776.

The square root of 6778393561 is 82331.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 670033225 + 6108360336 = 25885^2 + 78156^2 .

It is not a de Polignac number, because 6778393561 - 2⁵ = 6778393529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6778393571) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 40589100 + ... + 40589266.

Almost surely, 2^6778393561 is an apocalyptic number.

6778393561 is the 82331-st square number.

6778393561 is the 41166-th centered octagonal number.

It is an amenable number.

6778393561 is a deficient number, since it is larger than the sum of its proper divisors (723964068).

6778393561 is an equidigital number, since it uses as much as digits as its factorization.

6778393561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426 (or 213 counting only the distinct ones).

The product of its digits is 5715360, while the sum is 55.

The cubic root of 6778393561 is about 1892.5277675845.

The spelling of 6778393561 in words is "six billion, seven hundred seventy-eight million, three hundred ninety-three thousand, five hundred sixty-one".