800421808721 has 2 divisors, whose sum is σ = 800421808722. Its totient is φ = 800421808720.

The previous prime is 800421808687. The next prime is 800421808727. The reversal of 800421808721 is 127808124008.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 568155645121 + 232266163600 = 753761^2 + 481940^2 .

It is a cyclic number.

It is not a de Polignac number, because 800421808721 - 2²⁶ = 800354699857 is a prime.

It is a super-2 number, since 2×800421808721² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (800421808727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 400210904360 + 400210904361.

It is an arithmetic number, because the mean of its divisors is an integer number (400210904361).

Almost surely, 2^800421808721 is an apocalyptic number.

It is an amenable number.

800421808721 is a deficient number, since it is larger than the sum of its proper divisors (1).

800421808721 is an equidigital number, since it uses as much as digits as its factorization.

800421808721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 57344, while the sum is 41.

The spelling of 800421808721 in words is "eight hundred billion, four hundred twenty-one million, eight hundred eight thousand, seven hundred twenty-one".