9920905 has 4 divisors (see below), whose sum is σ = 11905092. Its totient is φ = 7936720.

The previous prime is 9920903. The next prime is 9920923. The reversal of 9920905 is 5090299.

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 2013561 + 7907344 = 1419^2 + 2812^2 .

It is not a de Polignac number, because 9920905 - 2¹ = 9920903 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9920903) by changing a digit.

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, 992086 + ... + 992095.

It is an arithmetic number, because the mean of its divisors is an integer number (2976273).

Almost surely, 2^9920905 is an apocalyptic number.

It is an amenable number.

9920905 is a deficient number, since it is larger than the sum of its proper divisors (1984187).

9920905 is a wasteful number, since it uses less digits than its factorization.

9920905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1984186.

The product of its (nonzero) digits is 7290, while the sum is 34.

The square root of 9920905 is about 3149.7468152218. The cubic root of 9920905 is about 214.8739481056.

It can be divided in two parts, 99 and 20905, that multiplied together give a triangular number (2069595 = T₂₀₃₄).

The spelling of 9920905 in words is "nine million, nine hundred twenty thousand, nine hundred five".