66057861816 has 96 divisors (see below), whose sum is σ = 185240811600. Its totient is φ = 21241059840.

The previous prime is 66057861791. The next prime is 66057861817. The reversal of 66057861816 is 61816875066.

66057861816 is a `hidden beast` number, since 6 + 6 + 0 + 5 + 7 + 8 + 618 + 16 = 666.

It is a super-2 number, since 2×66057861816² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66057861817) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2431540 + ... + 2458556.

Almost surely, 2^66057861816 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 66057861816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92620405800).

66057861816 is an abundant number, since it is smaller than the sum of its proper divisors (119182949784).

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

66057861816 is a wasteful number, since it uses less digits than its factorization.

66057861816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28229 (or 28222 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 54.

The spelling of 66057861816 in words is "sixty-six billion, fifty-seven million, eight hundred sixty-one thousand, eight hundred sixteen".