9661 has 2 divisors, whose sum is σ = 9662.
Its totient is φ = 9660.
The previous prime is 9649. The next prime is 9677. The reversal of 9661 is 1669.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 4900 + 4761 = 70^2 + 69^2
It is an emirp because it is prime and its reverse (1669) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 9661 - 25 = 9629 is a prime.
It is a Chen prime.
9661 is a lucky number.
It is a plaindrome in base 16.
It is a nialpdrome in base 10.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (9601) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4830 + 4831.
It is an arithmetic number, because the mean of its divisors is an integer number (4831).
29661 is an apocalyptic number.
9661 is the 70-th centered square number.
It is an amenable number.
9661 is a deficient number, since it is larger than the sum of its proper divisors (1).
9661 is an equidigital number, since it uses as much as digits as its factorization.
9661 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 324, while the sum is 22.
The square root of 9661 is about 98.2903861016.
The cubic root of 9661 is about 21.2980917714.
The spelling of 9661 in words is "nine thousand, six hundred sixty-one".