9661809 has 4 divisors (see below), whose sum is σ = 12882416. Its totient is φ = 6441204.

The previous prime is 9661787. The next prime is 9661829. The reversal of 9661809 is 9081669.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 9661809 - 2⁵ = 9661777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9661829) 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 in 3 ways as a sum of consecutive naturals, for example, 1610299 + ... + 1610304.

It is an arithmetic number, because the mean of its divisors is an integer number (3220604).

Almost surely, 2^9661809 is an apocalyptic number.

It is an amenable number.

9661809 is a deficient number, since it is larger than the sum of its proper divisors (3220607).

9661809 is a wasteful number, since it uses less digits than its factorization.

9661809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3220606.

The product of its (nonzero) digits is 23328, while the sum is 39.

The square root of 9661809 is about 3108.3450580655. The cubic root of 9661809 is about 212.9868624664.

It can be divided in two parts, 966 and 1809, that added together give a triangular number (2775 = T₇₄).

The spelling of 9661809 in words is "nine million, six hundred sixty-one thousand, eight hundred nine".