821997331853616 has 80 divisors (see below), whose sum is σ = 2372617997193600. Its totient is φ = 272468389303872.

The previous prime is 821997331853597. The next prime is 821997331853653. The reversal of 821997331853616 is 616358133799128.

821997331853616 is a `hidden beast` number, since 8 + 2 + 1 + 9 + 9 + 73 + 3 + 1 + 8 + 536 + 16 = 666.

821997331853616 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×821997331853616² (a number of 31 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5314927146 + ... + 5315081801.

It is an arithmetic number, because the mean of its divisors is an integer number (29657724964920).

Almost surely, 2^{821997331853616} is an apocalyptic number.

It is an amenable number.

821997331853616 is an abundant number, since it is smaller than the sum of its proper divisors (1550620665339984).

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

821997331853616 is a wasteful number, since it uses less digits than its factorization.

821997331853616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10630009143 (or 10630009131 counting only the distinct ones).

The product of its digits is 352719360, while the sum is 72.

The spelling of 821997331853616 in words is "eight hundred twenty-one trillion, nine hundred ninety-seven billion, three hundred thirty-one million, eight hundred fifty-three thousand, six hundred sixteen".