666617080320 has 240 divisors, whose sum is σ = 2310987444480. Its totient is φ = 177587085312.

The previous prime is 666617080303. The next prime is 666617080331. The reversal of 666617080320 is 23080716666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-3 number, since 3×666617080320³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23924637 + ... + 23952483.

It is an arithmetic number, because the mean of its divisors is an integer number (9629114352).

Almost surely, 2^666617080320 is an apocalyptic number.

666617080320 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 666617080320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1155493722240).

666617080320 is an abundant number, since it is smaller than the sum of its proper divisors (1644370364160).

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

666617080320 is a wasteful number, since it uses less digits than its factorization.

666617080320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28915 (or 28896 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

Adding to 666617080320 its reverse (23080716666), we get a palindrome (689697796986).

The spelling of 666617080320 in words is "six hundred sixty-six billion, six hundred seventeen million, eighty thousand, three hundred twenty".