66642616778 has 8 divisors (see below), whose sum is σ = 100751043072. Its totient is φ = 33058935756.

The previous prime is 66642616769. The next prime is 66642616787. The reversal of 66642616778 is 87761624666.

It is an interprime number because it is at equal distance from previous prime (66642616769) and next prime (66642616787).

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

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 3 ways as a sum of consecutive naturals, for example, 131186000 + ... + 131186507.

It is an arithmetic number, because the mean of its divisors is an integer number (12593880384).

Almost surely, 2^66642616778 is an apocalyptic number.

66642616778 is a deficient number, since it is larger than the sum of its proper divisors (34108426294).

66642616778 is a wasteful number, since it uses less digits than its factorization.

66642616778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262372636.

The product of its digits is 24385536, while the sum is 59.

The spelling of 66642616778 in words is "sixty-six billion, six hundred forty-two million, six hundred sixteen thousand, seven hundred seventy-eight".