9945665 has 4 divisors (see below), whose sum is σ = 11934804. Its totient is φ = 7956528.

The previous prime is 9945647. The next prime is 9945667. The reversal of 9945665 is 5665499.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5665499 = 7 ⋅809357.

It can be written as a sum of positive squares in 2 ways, for example, as 5180176 + 4765489 = 2276^2 + 2183^2 .

It is a cyclic number.

It is not a de Polignac number, because 9945665 - 2⁸ = 9945409 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9945667) 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, 994562 + ... + 994571.

It is an arithmetic number, because the mean of its divisors is an integer number (2983701).

Almost surely, 2^9945665 is an apocalyptic number.

It is an amenable number.

9945665 is a deficient number, since it is larger than the sum of its proper divisors (1989139).

9945665 is a wasteful number, since it uses less digits than its factorization.

9945665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1989138.

The product of its digits is 291600, while the sum is 44.

The square root of 9945665 is about 3153.6748405630. The cubic root of 9945665 is about 215.0525561080.

The spelling of 9945665 in words is "nine million, nine hundred forty-five thousand, six hundred sixty-five".