660587821920 has 432 divisors, whose sum is σ = 2443978293120. Its totient is φ = 162407890944.

The previous prime is 660587821913. The next prime is 660587821921. The reversal of 660587821920 is 29128785066.

660587821920 is a `hidden beast` number, since 6 + 605 + 8 + 7 + 8 + 2 + 1 + 9 + 20 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660587821921) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 362362129 + ... + 362363951.

It is an arithmetic number, because the mean of its divisors is an integer number (5657357160).

Almost surely, 2^660587821920 is an apocalyptic number.

660587821920 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 660587821920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1221989146560).

660587821920 is an abundant number, since it is smaller than the sum of its proper divisors (1783390471200).

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

660587821920 is a wasteful number, since it uses less digits than its factorization.

660587821920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3359 (or 3335 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 54.

The spelling of 660587821920 in words is "six hundred sixty billion, five hundred eighty-seven million, eight hundred twenty-one thousand, nine hundred twenty".