66669778 has 32 divisors (see below), whose sum is σ = 123125760. Its totient is φ = 26444880.

The previous prime is 66669773. The next prime is 66669787. The reversal of 66669778 is 87796666.

It is not an unprimeable number, because it can be changed into a prime (66669773) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6643 + ... + 13321.

It is an arithmetic number, because the mean of its divisors is an integer number (3847680).

Almost surely, 2^66669778 is an apocalyptic number.

66669778 is a deficient number, since it is larger than the sum of its proper divisors (56455982).

66669778 is a wasteful number, since it uses less digits than its factorization.

66669778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6742.

The product of its digits is 4572288, while the sum is 55.

The square root of 66669778 is about 8165.1563365315. The cubic root of 66669778 is about 405.4864408594.

The spelling of 66669778 in words is "sixty-six million, six hundred sixty-nine thousand, seven hundred seventy-eight".