66778785 has 24 divisors (see below), whose sum is σ = 118445184. Its totient is φ = 34786080.

The previous prime is 66778763. The next prime is 66778799. The reversal of 66778785 is 58787766.

It is not a de Polignac number, because 66778785 - 2⁵ = 66778753 is a prime.

It is a super-2 number, since 2×66778785² = 8918812252152450, which contains 22 as substring.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 15321 + ... + 19190.

It is an arithmetic number, because the mean of its divisors is an integer number (4935216).

Almost surely, 2^66778785 is an apocalyptic number.

It is an amenable number.

66778785 is a deficient number, since it is larger than the sum of its proper divisors (51666399).

66778785 is a wasteful number, since it uses less digits than its factorization.

66778785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34565 (or 34562 counting only the distinct ones).

The product of its digits is 3951360, while the sum is 54.

The square root of 66778785 is about 8171.8287426989. The cubic root of 66778785 is about 405.7073145133.

The spelling of 66778785 in words is "sixty-six million, seven hundred seventy-eight thousand, seven hundred eighty-five".