665859958566 has 32 divisors (see below), whose sum is σ = 1456680284928. Its totient is φ = 201234783840.

The previous prime is 665859958559. The next prime is 665859958573.

665859958566 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (665859958559) and next prime (665859958573).

It is a junction number, because it is equal to n+sod(n) for n = 665859958491 and 665859958500.

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 15 ways as a sum of consecutive naturals, for example, 13499226 + ... + 13548461.

It is an arithmetic number, because the mean of its divisors is an integer number (45521258904).

Almost surely, 2^665859958566 is an apocalyptic number.

665859958566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

665859958566 is an abundant number, since it is smaller than the sum of its proper divisors (790820326362).

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

665859958566 is a wasteful number, since it uses less digits than its factorization.

665859958566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27048076.

The product of its digits is 4199040000, while the sum is 78.

The spelling of 665859958566 in words is "six hundred sixty-five billion, eight hundred fifty-nine million, nine hundred fifty-eight thousand, five hundred sixty-six".