666204660 has 144 divisors (see below), whose sum is σ = 2300538240. Its totient is φ = 154471680.

The previous prime is 666204629. The next prime is 666204689. The reversal of 666204660 is 66402666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 38226 + ... + 52854.

It is an arithmetic number, because the mean of its divisors is an integer number (15975960).

Almost surely, 2^666204660 is an apocalyptic number.

666204660 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 666204660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1150269120).

666204660 is an abundant number, since it is smaller than the sum of its proper divisors (1634333580).

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

666204660 is a wasteful number, since it uses less digits than its factorization.

666204660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14678 (or 14673 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 666204660 is about 25810.9407035079. The cubic root of 666204660 is about 873.3786181026.

The spelling of 666204660 in words is "six hundred sixty-six million, two hundred four thousand, six hundred sixty".