22171561 has 2 divisors, whose sum is σ = 22171562. Its totient is φ = 22171560.

The previous prime is 22171559. The next prime is 22171601. The reversal of 22171561 is 16517122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11182336 + 10989225 = 3344^2 + 3315^2 .

It is a cyclic number.

It is not a de Polignac number, because 22171561 - 2¹ = 22171559 is a prime.

Together with 22171559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (22171511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11085780 + 11085781.

It is an arithmetic number, because the mean of its divisors is an integer number (11085781).

Almost surely, 2^22171561 is an apocalyptic number.

It is an amenable number.

22171561 is a deficient number, since it is larger than the sum of its proper divisors (1).

22171561 is an equidigital number, since it uses as much as digits as its factorization.

22171561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 840, while the sum is 25.

The square root of 22171561 is about 4708.6687078197. The cubic root of 22171561 is about 280.9304125589.

Adding to 22171561 its reverse (16517122), we get a palindrome (38688683).

The spelling of 22171561 in words is "twenty-two million, one hundred seventy-one thousand, five hundred sixty-one".