665814856 has 64 divisors (see below), whose sum is σ = 1492992000. Its totient is φ = 272171328.

The previous prime is 665814847. The next prime is 665814859. The reversal of 665814856 is 658418566.

It is not an unprimeable number, because it can be changed into a prime (665814859) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 771081 + ... + 771943.

It is an arithmetic number, because the mean of its divisors is an integer number (23328000).

Almost surely, 2^665814856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665814856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (746496000).

665814856 is an abundant number, since it is smaller than the sum of its proper divisors (827177144).

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

665814856 is a wasteful number, since it uses less digits than its factorization.

665814856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1498 (or 1494 counting only the distinct ones).

The product of its digits is 1382400, while the sum is 49.

The square root of 665814856 is about 25803.3884596578. The cubic root of 665814856 is about 873.2082435813.

The spelling of 665814856 in words is "six hundred sixty-five million, eight hundred fourteen thousand, eight hundred fifty-six".