777777777778 has 16 divisors (see below), whose sum is σ = 1167852394656. Its totient is φ = 388493837280.

The previous prime is 777777777773. The next prime is 777777777841. The reversal of 777777777778 is 877777777777.

It is a plaindrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 777777777695 and 777777777704.

It is not an unprimeable number, because it can be changed into a prime (777777777773) 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 in 7 ways as a sum of consecutive naturals, for example, 8478625 + ... + 8569867.

It is an arithmetic number, because the mean of its divisors is an integer number (72990774666).

Almost surely, 2^777777777778 is an apocalyptic number.

777777777778 is a deficient number, since it is larger than the sum of its proper divisors (390074616878).

777777777778 is a wasteful number, since it uses less digits than its factorization.

777777777778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95529.

The product of its digits is 15818613944, while the sum is 85.

Subtracting 777777777778 from its reverse (877777777777), we obtain a palindrome (99999999999).

It can be divided in two parts, 7777777777 and 78, that multiplied together give a palindrome (606666666606).

The spelling of 777777777778 in words is "seven hundred seventy-seven billion, seven hundred seventy-seven million, seven hundred seventy-seven thousand, seven hundred seventy-eight".