66817220261760 has 768 divisors, whose sum is σ = 257787288720000. Its totient is φ = 15860409827328.

The previous prime is 66817220261741. The next prime is 66817220261761. The reversal of 66817220261760 is 6716202271866.

It is a happy number.

66817220261760 is a `hidden beast` number, since 6 + 6 + 8 + 17 + 2 + 2 + 0 + 2 + 617 + 6 + 0 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 66817220261697 and 66817220261706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66817220261761) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 200275566 + ... + 200608914.

Almost surely, 2^{66817220261760} is an apocalyptic number.

66817220261760 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 66817220261760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128893644360000).

66817220261760 is an abundant number, since it is smaller than the sum of its proper divisors (190970068458240).

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

66817220261760 is a wasteful number, since it uses less digits than its factorization.

66817220261760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333503 (or 333488 counting only the distinct ones).

The product of its (nonzero) digits is 4064256, while the sum is 54.

The spelling of 66817220261760 in words is "sixty-six trillion, eight hundred seventeen billion, two hundred twenty million, two hundred sixty-one thousand, seven hundred sixty".