665503685280 has 960 divisors, whose sum is σ = 2745011808000. Its totient is φ = 148702003200.

The previous prime is 665503685279. The next prime is 665503685309. The reversal of 665503685280 is 82586305566.

665503685280 is a `hidden beast` number, since 6 + 6 + 5 + 50 + 3 + 68 + 528 + 0 = 666.

It is a super-2 number, since 2×665503685280² (a number of 24 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 1333674471 + ... + 1333674969.

It is an arithmetic number, because the mean of its divisors is an integer number (2859387300).

Almost surely, 2^665503685280 is an apocalyptic number.

665503685280 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 665503685280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1372505904000).

665503685280 is an abundant number, since it is smaller than the sum of its proper divisors (2079508122720).

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

665503685280 is a wasteful number, since it uses less digits than its factorization.

665503685280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 835 (or 818 counting only the distinct ones).

The product of its (nonzero) digits is 10368000, while the sum is 54.

The spelling of 665503685280 in words is "six hundred sixty-five billion, five hundred three million, six hundred eighty-five thousand, two hundred eighty".