665312071680 has 624 divisors, whose sum is σ = 2447950464960. Its totient is φ = 173234847744.

The previous prime is 665312071663. The next prime is 665312071681. The reversal of 665312071680 is 86170213566.

665312071680 is a `hidden beast` number, since 6 + 6 + 531 + 20 + 7 + 16 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (665312071681) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 213993966 + ... + 213997074.

It is an arithmetic number, because the mean of its divisors is an integer number (3922997540).

Almost surely, 2^665312071680 is an apocalyptic number.

665312071680 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 665312071680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1223975232480).

665312071680 is an abundant number, since it is smaller than the sum of its proper divisors (1782638393280).

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

665312071680 is an equidigital number, since it uses as much as digits as its factorization.

665312071680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3196 (or 3162 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 665312071680 in words is "six hundred sixty-five billion, three hundred twelve million, seventy-one thousand, six hundred eighty".