9940561 has 2 divisors, whose sum is σ = 9940562. Its totient is φ = 9940560.

The previous prime is 9940537. The next prime is 9940571. The reversal of 9940561 is 1650499.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8850625 + 1089936 = 2975^2 + 1044^2 .

It is a cyclic number.

It is not a de Polignac number, because 9940561 - 2⁷ = 9940433 is a prime.

It is equal to p₆₆₀₉₄₉ and since 9940561 and 660949 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (9940501) 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, 4970280 + 4970281.

It is an arithmetic number, because the mean of its divisors is an integer number (4970281).

Almost surely, 2^9940561 is an apocalyptic number.

It is an amenable number.

9940561 is a deficient number, since it is larger than the sum of its proper divisors (1).

9940561 is an equidigital number, since it uses as much as digits as its factorization.

9940561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 9940561 is about 3152.8655220291. The cubic root of 9940561 is about 215.0157623201.

It can be divided in two parts, 9940 and 561, that added together give a palindrome (10501).

The spelling of 9940561 in words is "nine million, nine hundred forty thousand, five hundred sixty-one".