2221222561 has 2 divisors, whose sum is σ = 2221222562. Its totient is φ = 2221222560.

The previous prime is 2221222559. The next prime is 2221222579. The reversal of 2221222561 is 1652221222.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2092513536 + 128709025 = 45744^2 + 11345^2 .

It is a cyclic number.

It is not a de Polignac number, because 2221222561 - 2¹ = 2221222559 is a prime.

Together with 2221222559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2221226561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1110611280 + 1110611281.

It is an arithmetic number, because the mean of its divisors is an integer number (1110611281).

Almost surely, 2^2221222561 is an apocalyptic number.

It is an amenable number.

2221222561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2221222561 is an equidigital number, since it uses as much as digits as its factorization.

2221222561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1920, while the sum is 25.

The square root of 2221222561 is about 47129.8478779637. The cubic root of 2221222561 is about 1304.7601739721.

Adding to 2221222561 its reverse (1652221222), we get a palindrome (3873443783).

The spelling of 2221222561 in words is "two billion, two hundred twenty-one million, two hundred twenty-two thousand, five hundred sixty-one".