861426506221 has 2 divisors, whose sum is σ = 861426506222. Its totient is φ = 861426506220.

The previous prime is 861426506201. The next prime is 861426506233. The reversal of 861426506221 is 122605624168.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 532810943721 + 328615562500 = 729939^2 + 573250^2 .

It is a cyclic number.

It is not a de Polignac number, because 861426506221 - 2¹¹ = 861426504173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861426506201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430713253110 + 430713253111.

It is an arithmetic number, because the mean of its divisors is an integer number (430713253111).

Almost surely, 2^861426506221 is an apocalyptic number.

It is an amenable number.

861426506221 is a deficient number, since it is larger than the sum of its proper divisors (1).

861426506221 is an equidigital number, since it uses as much as digits as its factorization.

861426506221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 276480, while the sum is 43.

The spelling of 861426506221 in words is "eight hundred sixty-one billion, four hundred twenty-six million, five hundred six thousand, two hundred twenty-one".