9909661 has 4 divisors (see below), whose sum is σ = 9934300. Its totient is φ = 9885024.

The previous prime is 9909649. The next prime is 9909667. The reversal of 9909661 is 1669099.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5152900 + 4756761 = 2270^2 + 2181^2 .

It is a cyclic number.

It is not a de Polignac number, because 9909661 - 2⁵ = 9909629 is a prime.

It is a super-2 number, since 2×9909661² = 196402762269842, which contains 22 as substring.

It is a Duffinian number.

9909661 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9909667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11706 + ... + 12523.

It is an arithmetic number, because the mean of its divisors is an integer number (2483575).

Almost surely, 2^9909661 is an apocalyptic number.

It is an amenable number.

9909661 is a deficient number, since it is larger than the sum of its proper divisors (24639).

9909661 is a wasteful number, since it uses less digits than its factorization.

9909661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24638.

The product of its (nonzero) digits is 26244, while the sum is 40.

The square root of 9909661 is about 3147.9614038295. The cubic root of 9909661 is about 214.7927405948.

The spelling of 9909661 in words is "nine million, nine hundred nine thousand, six hundred sixty-one".