66778478 has 8 divisors (see below), whose sum is σ = 107872968. Its totient is φ = 30820824.

The previous prime is 66778477. The next prime is 66778487. The reversal of 66778478 is 87487766.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66778471) 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 3 ways as a sum of consecutive naturals, for example, 1284176 + ... + 1284227.

It is an arithmetic number, because the mean of its divisors is an integer number (13484121).

Almost surely, 2^66778478 is an apocalyptic number.

66778478 is a deficient number, since it is larger than the sum of its proper divisors (41094490).

66778478 is a wasteful number, since it uses less digits than its factorization.

66778478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2568418.

The product of its digits is 3161088, while the sum is 53.

The square root of 66778478 is about 8171.8099586322. The cubic root of 66778478 is about 405.7066927972.

The spelling of 66778478 in words is "sixty-six million, seven hundred seventy-eight thousand, four hundred seventy-eight".