9991445 has 4 divisors (see below), whose sum is σ = 11989740. Its totient is φ = 7993152.

The previous prime is 9991441. The next prime is 9991451. The reversal of 9991445 is 5441999.

It is a happy number.

9991445 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5441999 = 19 ⋅286421.

It can be written as a sum of positive squares in 2 ways, for example, as 5635876 + 4355569 = 2374^2 + 2087^2 .

It is a cyclic number.

It is not a de Polignac number, because 9991445 - 2² = 9991441 is a prime.

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9991441) 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, 999140 + ... + 999149.

It is an arithmetic number, because the mean of its divisors is an integer number (2997435).

Almost surely, 2^9991445 is an apocalyptic number.

It is an amenable number.

9991445 is a deficient number, since it is larger than the sum of its proper divisors (1998295).

9991445 is a wasteful number, since it uses less digits than its factorization.

9991445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1998294.

The product of its digits is 58320, while the sum is 41.

The square root of 9991445 is about 3160.9247064744. The cubic root of 9991445 is about 215.3820141791.

The spelling of 9991445 in words is "nine million, nine hundred ninety-one thousand, four hundred forty-five".