813434221 has 2 divisors, whose sum is σ = 813434222. Its totient is φ = 813434220.

The previous prime is 813434197. The next prime is 813434227. The reversal of 813434221 is 122434318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 749992996 + 63441225 = 27386^2 + 7965^2 .

It is a cyclic number.

It is not a de Polignac number, because 813434221 - 2⁷ = 813434093 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 813434221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (813434227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406717110 + 406717111.

It is an arithmetic number, because the mean of its divisors is an integer number (406717111).

Almost surely, 2^813434221 is an apocalyptic number.

It is an amenable number.

813434221 is a deficient number, since it is larger than the sum of its proper divisors (1).

813434221 is an equidigital number, since it uses as much as digits as its factorization.

813434221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 28.

The square root of 813434221 is about 28520.7682400036. The cubic root of 813434221 is about 933.4852922504.

Adding to 813434221 its reverse (122434318), we get a palindrome (935868539).

The spelling of 813434221 in words is "eight hundred thirteen million, four hundred thirty-four thousand, two hundred twenty-one".