665828856 has 512 divisors, whose sum is σ = 2534400000. Its totient is φ = 160030080.

The previous prime is 665828773. The next prime is 665828861. The reversal of 665828856 is 658828566.

665828856 is a `hidden beast` number, since 6 + 6 + 582 + 8 + 8 + 56 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a zygodrome in base 7.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 15484371 + ... + 15484413.

It is an arithmetic number, because the mean of its divisors is an integer number (4950000).

Almost surely, 2^665828856 is an apocalyptic number.

665828856 is a gapful number since it is divisible by the number (66) 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 665828856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1267200000).

665828856 is an abundant number, since it is smaller than the sum of its proper divisors (1868571144).

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

665828856 is a wasteful number, since it uses less digits than its factorization.

665828856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 85 counting only the distinct ones).

The product of its digits is 5529600, while the sum is 54.

The square root of 665828856 is about 25803.6597404322. The cubic root of 665828856 is about 873.2143638160.

The spelling of 665828856 in words is "six hundred sixty-five million, eight hundred twenty-eight thousand, eight hundred fifty-six".