821685980 has 12 divisors (see below), whose sum is σ = 1725540600. Its totient is φ = 328674384.

The previous prime is 821685967. The next prime is 821686001. The reversal of 821685980 is 89586128.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 20542130 + ... + 20542169.

It is an arithmetic number, because the mean of its divisors is an integer number (143795050).

Almost surely, 2^821685980 is an apocalyptic number.

It is an amenable number.

821685980 is an abundant number, since it is smaller than the sum of its proper divisors (903854620).

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

821685980 is a wasteful number, since it uses less digits than its factorization.

821685980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41084308 (or 41084306 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 47.

The square root of 821685980 is about 28665.0654979192. The cubic root of 821685980 is about 936.6312112537.

The spelling of 821685980 in words is "eight hundred twenty-one million, six hundred eighty-five thousand, nine hundred eighty".