991478845 has 16 divisors (see below), whose sum is σ = 1439728128. Its totient is φ = 639878400.

The previous prime is 991478809. The next prime is 991478857. The reversal of 991478845 is 548874199.

It is a happy number.

991478845 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 991478845 - 2¹³ = 991470653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 832581 + ... + 833770.

It is an arithmetic number, because the mean of its divisors is an integer number (89983008).

Almost surely, 2^991478845 is an apocalyptic number.

It is an amenable number.

991478845 is a deficient number, since it is larger than the sum of its proper divisors (448249283).

991478845 is a wasteful number, since it uses less digits than its factorization.

991478845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1666380.

The product of its digits is 2903040, while the sum is 55.

The square root of 991478845 is about 31487.7570652468. The cubic root of 991478845 is about 997.1515088020.

The spelling of 991478845 in words is "nine hundred ninety-one million, four hundred seventy-eight thousand, eight hundred forty-five".