9991447 has 4 divisors (see below), whose sum is σ = 9997920. Its totient is φ = 9984976.

The previous prime is 9991441. The next prime is 9991451. The reversal of 9991447 is 7441999.

9991447 is digitally balanced in base 2 and base 3, because in such bases 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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 9991447 - 2³ = 9991439 is a prime.

It is an Ulam number.

It is a Duffinian 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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 579 + ... + 4507.

It is an arithmetic number, because the mean of its divisors is an integer number (2499480).

Almost surely, 2^9991447 is an apocalyptic number.

9991447 is a deficient number, since it is larger than the sum of its proper divisors (6473).

9991447 is a wasteful number, since it uses less digits than its factorization.

9991447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6472.

The product of its digits is 81648, while the sum is 43.

The square root of 9991447 is about 3160.9250228375. The cubic root of 9991447 is about 215.3820285502.

The spelling of 9991447 in words is "nine million, nine hundred ninety-one thousand, four hundred forty-seven".