665204678208 has 448 divisors, whose sum is σ = 2325009523200. Its totient is φ = 182473482240.

The previous prime is 665204678189. The next prime is 665204678221. The reversal of 665204678208 is 802876402566.

665204678208 is a `hidden beast` number, since 6 + 6 + 520 + 46 + 78 + 2 + 0 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (448).

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

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 63486666 + ... + 63497142.

It is an arithmetic number, because the mean of its divisors is an integer number (5189753400).

Almost surely, 2^665204678208 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 665204678208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1162504761600).

665204678208 is an abundant number, since it is smaller than the sum of its proper divisors (1659804844992).

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

665204678208 is a wasteful number, since it uses less digits than its factorization.

665204678208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10715 (or 10699 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 54.

The spelling of 665204678208 in words is "six hundred sixty-five billion, two hundred four million, six hundred seventy-eight thousand, two hundred eight".