820985647680 has 1344 divisors, whose sum is σ = 3450901708800. Its totient is φ = 183681146880.

The previous prime is 820985647663. The next prime is 820985647747. The reversal of 820985647680 is 86746589028.

820985647680 is a `hidden beast` number, since 8 + 2 + 0 + 9 + 8 + 564 + 7 + 68 + 0 = 666.

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 191 ways as a sum of consecutive naturals, for example, 570524401 + ... + 570525839.

It is an arithmetic number, because the mean of its divisors is an integer number (2567635200).

Almost surely, 2^820985647680 is an apocalyptic number.

820985647680 is a gapful number since it is divisible by the number (80) 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 820985647680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1725450854400).

820985647680 is an abundant number, since it is smaller than the sum of its proper divisors (2629916061120).

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

820985647680 is a wasteful number, since it uses less digits than its factorization.

820985647680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1534 (or 1512 counting only the distinct ones).

The product of its (nonzero) digits is 46448640, while the sum is 63.

The spelling of 820985647680 in words is "eight hundred twenty billion, nine hundred eighty-five million, six hundred forty-seven thousand, six hundred eighty".