820808264666 has 32 divisors (see below), whose sum is σ = 1404062145360. Its totient is φ = 356513181696.

The previous prime is 820808264641. The next prime is 820808264707. The reversal of 820808264666 is 666462808028.

It can be written as a sum of positive squares in 8 ways, for example, as 710853020641 + 109955244025 = 843121^2 + 331595^2 .

It is a Smith number, since the sum of its digits (56) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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, 4403390 + ... + 4586006.

Almost surely, 2^820808264666 is an apocalyptic number.

820808264666 is a deficient number, since it is larger than the sum of its proper divisors (583253880694).

820808264666 is a wasteful number, since it uses less digits than its factorization.

820808264666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192818.

The product of its (nonzero) digits is 10616832, while the sum is 56.

The spelling of 820808264666 in words is "eight hundred twenty billion, eight hundred eight million, two hundred sixty-four thousand, six hundred sixty-six".