665078561997696 has 7680 divisors, whose sum is σ = 2890732260556800. Its totient is φ = 149327268249600.

The previous prime is 665078561997679. The next prime is 665078561997767. The reversal of 665078561997696 is 696799165870566.

665078561997696 is a `hidden beast` number, since 6 + 6 + 507 + 8 + 5 + 6 + 1 + 9 + 9 + 7 + 6 + 96 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 959 ways as a sum of consecutive naturals, for example, 5236839070785 + ... + 5236839070911.

It is an arithmetic number, because the mean of its divisors is an integer number (376397429760).

Almost surely, 2^{665078561997696} is an apocalyptic number.

665078561997696 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 665078561997696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1445366130278400).

665078561997696 is an abundant number, since it is smaller than the sum of its proper divisors (2225653698559104).

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

665078561997696 is a wasteful number, since it uses less digits than its factorization.

665078561997696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 55553299200, while the sum is 90.

The spelling of 665078561997696 in words is "six hundred sixty-five trillion, seventy-eight billion, five hundred sixty-one million, nine hundred ninety-seven thousand, six hundred ninety-six".