665613717995520 has 3840 divisors, whose sum is σ = 2930410441728000. Its totient is φ = 142690222080000.

The previous prime is 665613717995519. The next prime is 665613717995557. The reversal of 665613717995520 is 25599717316566.

665613717995520 is a `hidden beast` number, since 6 + 6 + 5 + 6 + 1 + 3 + 7 + 1 + 7 + 9 + 95 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (3840).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 4408037867445 + ... + 4408037867595.

It is an arithmetic number, because the mean of its divisors is an integer number (763127719200).

Almost surely, 2^{665613717995520} is an apocalyptic number.

665613717995520 is a gapful number since it is divisible by the number (60) 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 665613717995520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1465205220864000).

665613717995520 is an abundant number, since it is smaller than the sum of its proper divisors (2264796723732480).

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

665613717995520 is an equidigital number, since it uses as much as digits as its factorization.

665613717995520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 642978000, while the sum is 72.

The spelling of 665613717995520 in words is "six hundred sixty-five trillion, six hundred thirteen billion, seven hundred seventeen million, nine hundred ninety-five thousand, five hundred twenty".