66887778 has 16 divisors (see below), whose sum is σ = 134019936. Its totient is φ = 22255200.

The previous prime is 66887761. The next prime is 66887797. The reversal of 66887778 is 87778866.

66887778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6523 + ... + 13278.

It is an arithmetic number, because the mean of its divisors is an integer number (8376246).

Almost surely, 2^66887778 is an apocalyptic number.

66887778 is an abundant number, since it is smaller than the sum of its proper divisors (67132158).

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

66887778 is a wasteful number, since it uses less digits than its factorization.

66887778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20369.

The product of its digits is 6322176, while the sum is 57.

The square root of 66887778 is about 8178.4948492984. The cubic root of 66887778 is about 405.9279196133.

The spelling of 66887778 in words is "sixty-six million, eight hundred eighty-seven thousand, seven hundred seventy-eight".