78621485666 has 16 divisors (see below), whose sum is σ = 121233863160. Its totient is φ = 38212202880.

The previous prime is 78621485659. The next prime is 78621485693. The reversal of 78621485666 is 66658412687.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 72978321025 + 5643164641 = 270145^2 + 75121^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 422171 + ... + 579198.

Almost surely, 2^78621485666 is an apocalyptic number.

78621485666 is a deficient number, since it is larger than the sum of its proper divisors (42612377494).

78621485666 is a wasteful number, since it uses less digits than its factorization.

78621485666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1002469.

The product of its digits is 23224320, while the sum is 59.

The spelling of 78621485666 in words is "seventy-eight billion, six hundred twenty-one million, four hundred eighty-five thousand, six hundred sixty-six".