800420305781 has 2 divisors, whose sum is σ = 800420305782. Its totient is φ = 800420305780.

The previous prime is 800420305733. The next prime is 800420305787. The reversal of 800420305781 is 187503024008.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 778613876881 + 21806428900 = 882391^2 + 147670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-800420305781 is a prime.

It is a super-2 number, since 2×800420305781² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (800420305787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 400210152890 + 400210152891.

It is an arithmetic number, because the mean of its divisors is an integer number (400210152891).

Almost surely, 2^800420305781 is an apocalyptic number.

It is an amenable number.

800420305781 is a deficient number, since it is larger than the sum of its proper divisors (1).

800420305781 is an equidigital number, since it uses as much as digits as its factorization.

800420305781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 53760, while the sum is 38.

Adding to 800420305781 its reverse (187503024008), we get a palindrome (987923329789).

The spelling of 800420305781 in words is "eight hundred billion, four hundred twenty million, three hundred five thousand, seven hundred eighty-one".