66849105780 has 432 divisors, whose sum is σ = 228460783824. Its totient is φ = 15761940480.

The previous prime is 66849105773. The next prime is 66849105821. The reversal of 66849105780 is 8750194866.

66849105780 is a `hidden beast` number, since 6 + 68 + 4 + 9 + 1 + 0 + 578 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 1106094564 + 65743011216 = 33258^2 + 256404^2 .

It is a super-3 number, since 3×66849105780³ (a number of 33 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 98742802 + ... + 98743478.

It is an arithmetic number, because the mean of its divisors is an integer number (528844407).

Almost surely, 2^66849105780 is an apocalyptic number.

66849105780 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66849105780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114230391912).

66849105780 is an abundant number, since it is smaller than the sum of its proper divisors (161611678044).

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

66849105780 is a wasteful number, since it uses less digits than its factorization.

66849105780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 816 (or 788 counting only the distinct ones).

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

The spelling of 66849105780 in words is "sixty-six billion, eight hundred forty-nine million, one hundred five thousand, seven hundred eighty".