9639661 has 2 divisors, whose sum is σ = 9639662. Its totient is φ = 9639660.

The previous prime is 9639649. The next prime is 9639671. The reversal of 9639661 is 1669369.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9418761 + 220900 = 3069^2 + 470^2 .

It is a cyclic number.

It is not a de Polignac number, because 9639661 - 2⁷ = 9639533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9639601) 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, 4819830 + 4819831.

It is an arithmetic number, because the mean of its divisors is an integer number (4819831).

Almost surely, 2^9639661 is an apocalyptic number.

9639661 is the 1389-th centered decagonal number.

It is an amenable number.

9639661 is a deficient number, since it is larger than the sum of its proper divisors (1).

9639661 is an equidigital number, since it uses as much as digits as its factorization.

9639661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52488, while the sum is 40.

The square root of 9639661 is about 3104.7803464980. The cubic root of 9639661 is about 212.8239929629.

The spelling of 9639661 in words is "nine million, six hundred thirty-nine thousand, six hundred sixty-one".