666499680 has 288 divisors, whose sum is σ = 2836124928. Its totient is φ = 138470400.

The previous prime is 666499679. The next prime is 666499741. The reversal of 666499680 is 86994666.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (288).

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 47 ways as a sum of consecutive naturals, for example, 107875 + ... + 113885.

It is an arithmetic number, because the mean of its divisors is an integer number (9847656).

Almost surely, 2^666499680 is an apocalyptic number.

666499680 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 666499680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1418062464).

666499680 is an abundant number, since it is smaller than the sum of its proper divisors (2169625248).

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

666499680 is a wasteful number, since it uses less digits than its factorization.

666499680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6050 (or 6039 counting only the distinct ones).

The product of its (nonzero) digits is 3359232, while the sum is 54.

The square root of 666499680 is about 25816.6550893023. The cubic root of 666499680 is about 873.5075205007.

The spelling of 666499680 in words is "six hundred sixty-six million, four hundred ninety-nine thousand, six hundred eighty".