665025520566 has 128 divisors (see below), whose sum is σ = 1499005896192. Its totient is φ = 194918400000.

The previous prime is 665025520561. The next prime is 665025520571.

665025520566 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (665025520561) and next prime (665025520571).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665025520561) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 576777846 + ... + 576778998.

It is an arithmetic number, because the mean of its divisors is an integer number (11710983564).

Almost surely, 2^665025520566 is an apocalyptic number.

665025520566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 665025520566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (749502948096).

665025520566 is an abundant number, since it is smaller than the sum of its proper divisors (833980375626).

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

665025520566 is a wasteful number, since it uses less digits than its factorization.

665025520566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2398.

The product of its (nonzero) digits is 3240000, while the sum is 48.

The spelling of 665025520566 in words is "six hundred sixty-five billion, twenty-five million, five hundred twenty thousand, five hundred sixty-six".