6778557867745 has 8 divisors (see below), whose sum is σ = 8143761009384. Its totient is φ = 5416518582144.

The previous prime is 6778557867733. The next prime is 6778557867749. The reversal of 6778557867745 is 5477687558776.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 489878207569 + 6288679660176 = 699913^2 + 2507724^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6778557867745 - 2²¹ = 6778555770593 is a prime.

It is a super-2 number, since 2×6778557867745² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6778557867749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 790959294 + ... + 790967863.

It is an arithmetic number, because the mean of its divisors is an integer number (1017970126173).

Almost surely, 2^{6778557867745} is an apocalyptic number.

It is an amenable number.

6778557867745 is a deficient number, since it is larger than the sum of its proper divisors (1365203141639).

6778557867745 is a wasteful number, since it uses less digits than its factorization.

6778557867745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1581928019.

The product of its digits is 19361664000, while the sum is 82.

The spelling of 6778557867745 in words is "six trillion, seven hundred seventy-eight billion, five hundred fifty-seven million, eight hundred sixty-seven thousand, seven hundred forty-five".