9920665 has 4 divisors (see below), whose sum is σ = 11904804. Its totient is φ = 7936528.

The previous prime is 9920657. The next prime is 9920671. The reversal of 9920665 is 5660299.

It is a happy number.

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 4575321 + 5345344 = 2139^2 + 2312^2 .

It is a cyclic number.

It is not a de Polignac number, because 9920665 - 2³ = 9920657 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 992062 + ... + 992071.

It is an arithmetic number, because the mean of its divisors is an integer number (2976201).

Almost surely, 2^9920665 is an apocalyptic number.

It is an amenable number.

9920665 is a deficient number, since it is larger than the sum of its proper divisors (1984139).

9920665 is a wasteful number, since it uses less digits than its factorization.

9920665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1984138.

The product of its (nonzero) digits is 29160, while the sum is 37.

The square root of 9920665 is about 3149.7087166911. The cubic root of 9920665 is about 214.8722153953.

It can be divided in two parts, 9920 and 665, that added together give a triangular number (10585 = T₁₄₅).

The spelling of 9920665 in words is "nine million, nine hundred twenty thousand, six hundred sixty-five".