66777777789 has 32 divisors (see below), whose sum is σ = 93606395904. Its totient is φ = 42263443200.

The previous prime is 66777777779. The next prime is 66777777791. The reversal of 66777777789 is 98777777766.

It is not a de Polignac number, because 66777777789 - 2⁸ = 66777777533 is a prime.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66777777779) 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 31 ways as a sum of consecutive naturals, for example, 16178644 + ... + 16182770.

It is an arithmetic number, because the mean of its divisors is an integer number (2925199872).

Almost surely, 2^66777777789 is an apocalyptic number.

66777777789 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

It is an amenable number.

66777777789 is a deficient number, since it is larger than the sum of its proper divisors (26828618115).

66777777789 is a wasteful number, since it uses less digits than its factorization.

66777777789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5857.

The product of its digits is 2134623456, while the sum is 78.

The spelling of 66777777789 in words is "sixty-six billion, seven hundred seventy-seven million, seven hundred seventy-seven thousand, seven hundred eighty-nine".