22981561 has 2 divisors, whose sum is σ = 22981562. Its totient is φ = 22981560.

The previous prime is 22981559. The next prime is 22981573. The reversal of 22981561 is 16518922.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11799225 + 11182336 = 3435^2 + 3344^2 .

It is a cyclic number.

It is not a de Polignac number, because 22981561 - 2¹ = 22981559 is a prime.

Together with 22981559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (22981591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11490780 + 11490781.

It is an arithmetic number, because the mean of its divisors is an integer number (11490781).

Almost surely, 2^22981561 is an apocalyptic number.

It is an amenable number.

22981561 is a deficient number, since it is larger than the sum of its proper divisors (1).

22981561 is an equidigital number, since it uses as much as digits as its factorization.

22981561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 34.

The square root of 22981561 is about 4793.9087392231. The cubic root of 22981561 is about 284.3106804741.

The spelling of 22981561 in words is "twenty-two million, nine hundred eighty-one thousand, five hundred sixty-one".