666566765568 has 440 divisors, whose sum is σ = 2241595090944. Its totient is φ = 195465830400.

The previous prime is 666566765539. The next prime is 666566765587. The reversal of 666566765568 is 865567665666.

It is a happy number.

It is a super-2 number, since 2×666566765568² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 666566765496 and 666566765505.

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 39 ways as a sum of consecutive naturals, for example, 28272121 + ... + 28295687.

Almost surely, 2^666566765568 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 666566765568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1120797545472).

666566765568 is an abundant number, since it is smaller than the sum of its proper divisors (1575028325376).

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

666566765568 is a wasteful number, since it uses less digits than its factorization.

666566765568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23641 (or 23614 counting only the distinct ones).

The product of its digits is 1959552000, while the sum is 72.

The spelling of 666566765568 in words is "six hundred sixty-six billion, five hundred sixty-six million, seven hundred sixty-five thousand, five hundred sixty-eight".