66756778 has 16 divisors (see below), whose sum is σ = 109672704. Its totient is φ = 30223360.

The previous prime is 66756761. The next prime is 66756791. The reversal of 66756778 is 87765766.

It is a zygodrome in base 4.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 250 + ... + 11557.

It is an arithmetic number, because the mean of its divisors is an integer number (6854544).

Almost surely, 2^66756778 is an apocalyptic number.

66756778 is a deficient number, since it is larger than the sum of its proper divisors (42915926).

66756778 is a wasteful number, since it uses less digits than its factorization.

66756778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12077.

The product of its digits is 2963520, while the sum is 52.

The square root of 66756778 is about 8170.4821155180. The cubic root of 66756778 is about 405.6627425641.

The spelling of 66756778 in words is "sixty-six million, seven hundred fifty-six thousand, seven hundred seventy-eight".