22111561 has 2 divisors, whose sum is σ = 22111562. Its totient is φ = 22111560.

The previous prime is 22111559. The next prime is 22111571. The reversal of 22111561 is 16511122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14017536 + 8094025 = 3744^2 + 2845^2 .

It is a cyclic number.

It is not a de Polignac number, because 22111561 - 2¹ = 22111559 is a prime.

It is a super-2 number, since 2×22111561² = 977842259713442, which contains 22 as substring.

Together with 22111559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (22111571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11055780 + 11055781.

It is an arithmetic number, because the mean of its divisors is an integer number (11055781).

Almost surely, 2^22111561 is an apocalyptic number.

It is an amenable number.

22111561 is a deficient number, since it is larger than the sum of its proper divisors (1).

22111561 is an equidigital number, since it uses as much as digits as its factorization.

22111561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120, while the sum is 19.

The square root of 22111561 is about 4702.2931639786. The cubic root of 22111561 is about 280.6767685242.

Adding to 22111561 its reverse (16511122), we get a palindrome (38622683).

The spelling of 22111561 in words is "twenty-two million, one hundred eleven thousand, five hundred sixty-one".