66558366810 has 288 divisors, whose sum is σ = 191111160240. Its totient is φ = 16061939712.

The previous prime is 66558366793. The next prime is 66558366829. The reversal of 66558366810 is 1866385566.

66558366810 is a `hidden beast` number, since 6 + 6 + 558 + 3 + 6 + 6 + 81 + 0 = 666.

It can be written as a sum of positive squares in 24 ways, for example, as 592094889 + 65966271921 = 24333^2 + 256839^2 .

It is a super-2 number, since 2×66558366810² (a number of 22 digits) contains 22 as substring.

It is a Curzon number.

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 143 ways as a sum of consecutive naturals, for example, 290647776 + ... + 290648004.

Almost surely, 2^66558366810 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66558366810, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95555580120).

66558366810 is an abundant number, since it is smaller than the sum of its proper divisors (124552793430).

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

66558366810 is a wasteful number, since it uses less digits than its factorization.

66558366810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 562 (or 546 counting only the distinct ones).

The product of its (nonzero) digits is 6220800, while the sum is 54.

The spelling of 66558366810 in words is "sixty-six billion, five hundred fifty-eight million, three hundred sixty-six thousand, eight hundred ten".