809820001 has 2 divisors, whose sum is σ = 809820002. Its totient is φ = 809820000.

The previous prime is 809819993. The next prime is 809820013. The reversal of 809820001 is 100028908.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 775901025 + 33918976 = 27855^2 + 5824^2 .

It is a cyclic number.

It is not a de Polignac number, because 809820001 - 2³ = 809819993 is a prime.

It is not a weakly prime, because it can be changed into another prime (809820091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404910000 + 404910001.

It is an arithmetic number, because the mean of its divisors is an integer number (404910001).

Almost surely, 2^809820001 is an apocalyptic number.

It is an amenable number.

809820001 is a deficient number, since it is larger than the sum of its proper divisors (1).

809820001 is an equidigital number, since it uses as much as digits as its factorization.

809820001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 809820001 is about 28457.3365057238. The cubic root of 809820001 is about 932.1006974432.

Adding to 809820001 its reverse (100028908), we get a palindrome (909848909).

It can be divided in two parts, 80982000 and 1, that added together give a square (80982001 = 8999²).

The spelling of 809820001 in words is "eight hundred nine million, eight hundred twenty thousand, one".