664841535666 has 128 divisors (see below), whose sum is σ = 1710365386752. Its totient is φ = 168669547200.

The previous prime is 664841535647. The next prime is 664841535671. The reversal of 664841535666 is 666535148466.

It is a super-3 number, since 3×664841535666³ (a number of 36 digits) contains 333 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2265496 + ... + 2542076.

It is an arithmetic number, because the mean of its divisors is an integer number (13362229584).

Almost surely, 2^664841535666 is an apocalyptic number.

664841535666 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 664841535666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (855182693376).

664841535666 is an abundant number, since it is smaller than the sum of its proper divisors (1045523851086).

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

664841535666 is a wasteful number, since it uses less digits than its factorization.

664841535666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276669 (or 276647 counting only the distinct ones).

The product of its digits is 74649600, while the sum is 60.

The spelling of 664841535666 in words is "six hundred sixty-four billion, eight hundred forty-one million, five hundred thirty-five thousand, six hundred sixty-six".