9818561 has 2 divisors, whose sum is σ = 9818562. Its totient is φ = 9818560.

The previous prime is 9818551. The next prime is 9818563. The reversal of 9818561 is 1658189.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5640625 + 4177936 = 2375^2 + 2044^2 .

It is a cyclic number.

It is not a de Polignac number, because 9818561 - 2¹⁰ = 9817537 is a prime.

It is a super-2 number, since 2×9818561² = 192808280221442, which contains 22 as substring.

Together with 9818563, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (9818563) 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, 4909280 + 4909281.

It is an arithmetic number, because the mean of its divisors is an integer number (4909281).

Almost surely, 2^9818561 is an apocalyptic number.

It is an amenable number.

9818561 is a deficient number, since it is larger than the sum of its proper divisors (1).

9818561 is an equidigital number, since it uses as much as digits as its factorization.

9818561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 38.

The square root of 9818561 is about 3133.4583131103. The cubic root of 9818561 is about 214.1325132058.

The spelling of 9818561 in words is "nine million, eight hundred eighteen thousand, five hundred sixty-one".