22081561 has 2 divisors, whose sum is σ = 22081562. Its totient is φ = 22081560.

The previous prime is 22081481. The next prime is 22081567. The reversal of 22081561 is 16518022.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21678336 + 403225 = 4656^2 + 635^2 .

It is a cyclic number.

It is not a de Polignac number, because 22081561 - 2⁹ = 22081049 is a prime.

It is not a weakly prime, because it can be changed into another prime (22081567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11040780 + 11040781.

It is an arithmetic number, because the mean of its divisors is an integer number (11040781).

Almost surely, 2^22081561 is an apocalyptic number.

It is an amenable number.

22081561 is a deficient number, since it is larger than the sum of its proper divisors (1).

22081561 is an equidigital number, since it uses as much as digits as its factorization.

22081561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 22081561 is about 4699.1021482832. The cubic root of 22081561 is about 280.5497744142.

Subtracting from 22081561 its product of nonzero digits (960), we obtain a square (22080601 = 4699²).

Adding to 22081561 its reverse (16518022), we get a palindrome (38599583).

The spelling of 22081561 in words is "twenty-two million, eighty-one thousand, five hundred sixty-one".