9643661 has 2 divisors, whose sum is σ = 9643662. Its totient is φ = 9643660.

The previous prime is 9643603. The next prime is 9643663. The reversal of 9643661 is 1663469.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7022500 + 2621161 = 2650^2 + 1619^2 .

It is a cyclic number.

It is not a de Polignac number, because 9643661 - 2¹⁰ = 9642637 is a prime.

Together with 9643663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9643663) 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, 4821830 + 4821831.

It is an arithmetic number, because the mean of its divisors is an integer number (4821831).

Almost surely, 2^9643661 is an apocalyptic number.

It is an amenable number.

9643661 is a deficient number, since it is larger than the sum of its proper divisors (1).

9643661 is an equidigital number, since it uses as much as digits as its factorization.

9643661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 35.

The square root of 9643661 is about 3105.4244476400. The cubic root of 9643661 is about 212.8534261643.

The spelling of 9643661 in words is "nine million, six hundred forty-three thousand, six hundred sixty-one".