665857709712 has 360 divisors, whose sum is σ = 2105759326944. Its totient is φ = 203589614592.

The previous prime is 665857709683. The next prime is 665857709743. The reversal of 665857709712 is 217907758566.

665857709712 is a `hidden beast` number, since 6 + 6 + 58 + 577 + 0 + 9 + 7 + 1 + 2 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 665857709712.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 107099628 + ... + 107105844.

Almost surely, 2^665857709712 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 665857709712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1052879663472).

665857709712 is an abundant number, since it is smaller than the sum of its proper divisors (1439901617232).

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

665857709712 is a wasteful number, since it uses less digits than its factorization.

665857709712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6429 (or 6398 counting only the distinct ones).

The product of its (nonzero) digits is 44452800, while the sum is 63.

The spelling of 665857709712 in words is "six hundred sixty-five billion, eight hundred fifty-seven million, seven hundred nine thousand, seven hundred twelve".