66778 has 8 divisors (see below), whose sum is σ = 101268. Its totient is φ = 33024.

The previous prime is 66763. The next prime is 66791. The reversal of 66778 is 87766.

It can be written as a sum of positive squares in 2 ways, for example, as 66049 + 729 = 257^2 + 27^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a plaindrome in base 10 and base 15.

It is an unprimeable number.

66778 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 250 + ... + 442.

2⁶⁶⁷⁷⁸ is an apocalyptic number.

66778 is a deficient number, since it is larger than the sum of its proper divisors (34490).

66778 is a wasteful number, since it uses less digits than its factorization.

66778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368.

The product of its digits is 14112, while the sum is 34.

The square root of 66778 is about 258.4143958838. The cubic root of 66778 is about 40.5705724779.

The spelling of 66778 in words is "sixty-six thousand, seven hundred seventy-eight".