66666777788 has 72 divisors (see below), whose sum is σ = 139270260192. Its totient is φ = 27700079616.

The previous prime is 66666777787. The next prime is 66666777847. The reversal of 66666777788 is 88777766666.

It is a super-3 number, since 3×66666777788³ (a number of 33 digits) contains 333 as substring.

It is a plaindrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66666777787) 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 23 ways as a sum of consecutive naturals, for example, 249206 + ... + 442082.

Almost surely, 2^66666777788 is an apocalyptic number.

66666777788 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

66666777788 is an abundant number, since it is smaller than the sum of its proper divisors (72603482404).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66666777788 is a wasteful number, since it uses less digits than its factorization.

66666777788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192951 (or 192932 counting only the distinct ones).

The product of its digits is 1194891264, while the sum is 74.

The spelling of 66666777788 in words is "sixty-six billion, six hundred sixty-six million, seven hundred seventy-seven thousand, seven hundred eighty-eight".