665982856 has 64 divisors (see below), whose sum is σ = 1590036480. Its totient is φ = 253942080.

The previous prime is 665982841. The next prime is 665982857. The reversal of 665982856 is 658289566.

It is a junction number, because it is equal to n+sod(n) for n = 665982797 and 665982806.

It is not an unprimeable number, because it can be changed into a prime (665982857) 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, 17451 + ... + 40453.

It is an arithmetic number, because the mean of its divisors is an integer number (24844320).

Almost surely, 2^665982856 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 665982856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (795018240).

665982856 is an abundant number, since it is smaller than the sum of its proper divisors (924053624).

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

665982856 is a wasteful number, since it uses less digits than its factorization.

665982856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23074 (or 23070 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 55.

The square root of 665982856 is about 25806.6436407372. The cubic root of 665982856 is about 873.2816807372.

The spelling of 665982856 in words is "six hundred sixty-five million, nine hundred eighty-two thousand, eight hundred fifty-six".