2561106221 has 2 divisors, whose sum is σ = 2561106222. Its totient is φ = 2561106220.

The previous prime is 2561106193. The next prime is 2561106239. The reversal of 2561106221 is 1226011652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1446280900 + 1114825321 = 38030^2 + 33389^2 .

It is a cyclic number.

It is not a de Polignac number, because 2561106221 - 2¹⁴ = 2561089837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2521106221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280553110 + 1280553111.

It is an arithmetic number, because the mean of its divisors is an integer number (1280553111).

Almost surely, 2^2561106221 is an apocalyptic number.

It is an amenable number.

2561106221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561106221 is an equidigital number, since it uses as much as digits as its factorization.

2561106221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 2561106221 is about 50607.3731881037. The cubic root of 2561106221 is about 1368.1777718102.

Adding to 2561106221 its reverse (1226011652), we get a palindrome (3787117873).

The spelling of 2561106221 in words is "two billion, five hundred sixty-one million, one hundred six thousand, two hundred twenty-one".