66478686768 has 400 divisors, whose sum is σ = 217433166720. Its totient is φ = 19470108672.

The previous prime is 66478686749. The next prime is 66478686773. The reversal of 66478686768 is 86768687466.

66478686768 is a `hidden beast` number, since 6 + 6 + 478 + 6 + 86 + 76 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 66478686696 and 66478686705.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 29297538 + ... + 29299806.

Almost surely, 2^66478686768 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66478686768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108716583360).

66478686768 is an abundant number, since it is smaller than the sum of its proper divisors (150954479952).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66478686768 is a wasteful number, since it uses less digits than its factorization.

66478686768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2386 (or 2371 counting only the distinct ones).

The product of its digits is 780337152, while the sum is 72.

The spelling of 66478686768 in words is "sixty-six billion, four hundred seventy-eight million, six hundred eighty-six thousand, seven hundred sixty-eight".