20800820840 has 16 divisors (see below), whose sum is σ = 46801846980. Its totient is φ = 8320328320.

The previous prime is 20800820809. The next prime is 20800820863. The reversal of 20800820840 is 4802800802.

It can be written as a sum of positive squares in 2 ways, for example, as 19564735876 + 1236084964 = 139874^2 + 35158^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20800820797 and 20800820806.

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, 260010221 + ... + 260010300.

Almost surely, 2^20800820840 is an apocalyptic number.

20800820840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20800820840 is an abundant number, since it is smaller than the sum of its proper divisors (26001026140).

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

20800820840 is a wasteful number, since it uses less digits than its factorization.

20800820840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520020532 (or 520020528 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 32.

The spelling of 20800820840 in words is "twenty billion, eight hundred million, eight hundred twenty thousand, eight hundred forty".