820999871993 has 8 divisors (see below), whose sum is σ = 942178871040. Its totient is φ = 700794198720.

The previous prime is 820999871983. The next prime is 820999872031. The reversal of 820999871993 is 399178999028.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 820999871993 - 2⁸ = 820999871737 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 820999871993.

It is not an unprimeable number, because it can be changed into a prime (820999871933) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 243329633 + ... + 243333006.

It is an arithmetic number, because the mean of its divisors is an integer number (117772358880).

Almost surely, 2^820999871993 is an apocalyptic number.

It is an amenable number.

820999871993 is a deficient number, since it is larger than the sum of its proper divisors (121178999047).

820999871993 is a wasteful number, since it uses less digits than its factorization.

820999871993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486662887.

The product of its (nonzero) digits is 158723712, while the sum is 74.

The spelling of 820999871993 in words is "eight hundred twenty billion, nine hundred ninety-nine million, eight hundred seventy-one thousand, nine hundred ninety-three".