9621561606689 has 2 divisors, whose sum is σ = 9621561606690. Its totient is φ = 9621561606688.

The previous prime is 9621561606637. The next prime is 9621561606809. The reversal of 9621561606689 is 9866061651269.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6117113958400 + 3504447648289 = 2473280^2 + 1872017^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9621561606689 is a prime.

It is a super-3 number, since 3×9621561606689³ (a number of 40 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (9621561606989) 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, 4810780803344 + 4810780803345.

It is an arithmetic number, because the mean of its divisors is an integer number (4810780803345).

Almost surely, 2^{9621561606689} is an apocalyptic number.

It is an amenable number.

9621561606689 is a deficient number, since it is larger than the sum of its proper divisors (1).

9621561606689 is an equidigital number, since it uses as much as digits as its factorization.

9621561606689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 50388480, while the sum is 65.

The spelling of 9621561606689 in words is "nine trillion, six hundred twenty-one billion, five hundred sixty-one million, six hundred six thousand, six hundred eighty-nine".