800105021 has 2 divisors, whose sum is σ = 800105022. Its totient is φ = 800105020.

The previous prime is 800104997. The next prime is 800105093. The reversal of 800105021 is 120501008.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 800097796 + 7225 = 28286^2 + 85^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-800105021 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (800105321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 400052510 + 400052511.

It is an arithmetic number, because the mean of its divisors is an integer number (400052511).

Almost surely, 2^800105021 is an apocalyptic number.

It is an amenable number.

800105021 is a deficient number, since it is larger than the sum of its proper divisors (1).

800105021 is an equidigital number, since it uses as much as digits as its factorization.

800105021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 800105021 is about 28286.1277130681. The cubic root of 800105021 is about 928.3583869702.

Adding to 800105021 its reverse (120501008), we get a palindrome (920606029).

The spelling of 800105021 in words is "eight hundred million, one hundred five thousand, twenty-one".