9991523 has 8 divisors (see below), whose sum is σ = 10270128. Its totient is φ = 9715104.

The previous prime is 9991489. The next prime is 9991543. The reversal of 9991523 is 3251999.

9991523 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 sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 9991523 - 2¹⁰ = 9990499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9991543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13265 + ... + 13997.

It is an arithmetic number, because the mean of its divisors is an integer number (1283766).

Almost surely, 2^9991523 is an apocalyptic number.

9991523 is a deficient number, since it is larger than the sum of its proper divisors (278605).

9991523 is a wasteful number, since it uses less digits than its factorization.

9991523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1093.

The product of its digits is 21870, while the sum is 38.

The square root of 9991523 is about 3160.9370446119. The cubic root of 9991523 is about 215.3825746503.

The spelling of 9991523 in words is "nine million, nine hundred ninety-one thousand, five hundred twenty-three".