66513806515856 has 40 divisors (see below), whose sum is σ = 147281017887744. Its totient is φ = 28505830694400.

The previous prime is 66513806515817. The next prime is 66513806515901. The reversal of 66513806515856 is 65851560831566.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 66513806515792 and 66513806515801.

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, 48067256 + ... + 49431656.

Almost surely, 2^{66513806515856} is an apocalyptic number.

It is an amenable number.

66513806515856 is an abundant number, since it is smaller than the sum of its proper divisors (80767211371888).

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

66513806515856 is a wasteful number, since it uses less digits than its factorization.

66513806515856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1799679 (or 1799673 counting only the distinct ones).

The product of its (nonzero) digits is 155520000, while the sum is 65.

The spelling of 66513806515856 in words is "sixty-six trillion, five hundred thirteen billion, eight hundred six million, five hundred fifteen thousand, eight hundred fifty-six".