78181583666 has 8 divisors (see below), whose sum is σ = 119194873644. Its totient is φ = 38449959120.

The previous prime is 78181583657. The next prime is 78181583699. The reversal of 78181583666 is 66638518187.

It can be written as a sum of positive squares in 2 ways, for example, as 78178956025 + 2627641 = 279605^2 + 1621^2 .

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

It is a super-2 number, since 2×78181583666² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

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, 320416205 + ... + 320416448.

Almost surely, 2^78181583666 is an apocalyptic number.

78181583666 is a deficient number, since it is larger than the sum of its proper divisors (41013289978).

78181583666 is a wasteful number, since it uses less digits than its factorization.

78181583666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640832716.

The product of its digits is 11612160, while the sum is 59.

The spelling of 78181583666 in words is "seventy-eight billion, one hundred eighty-one million, five hundred eighty-three thousand, six hundred sixty-six".