820660708791 has 48 divisors (see below), whose sum is σ = 1492248476160. Its totient is φ = 422178212160.

The previous prime is 820660708789. The next prime is 820660708793. The reversal of 820660708791 is 197807066028.

820660708791 is a `hidden beast` number, since 8 + 20 + 6 + 607 + 0 + 8 + 7 + 9 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (820660708789) and next prime (820660708793).

It is not a de Polignac number, because 820660708791 - 2¹ = 820660708789 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820660708793) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5677236 + ... + 5819993.

It is an arithmetic number, because the mean of its divisors is an integer number (31088509920).

Almost surely, 2^820660708791 is an apocalyptic number.

820660708791 is a deficient number, since it is larger than the sum of its proper divisors (671587767369).

820660708791 is a wasteful number, since it uses less digits than its factorization.

820660708791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11497356 (or 11497353 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 54.

The spelling of 820660708791 in words is "eight hundred twenty billion, six hundred sixty million, seven hundred eight thousand, seven hundred ninety-one".