9991563 has 8 divisors (see below), whose sum is σ = 14105808. Its totient is φ = 6269184.

The previous prime is 9991559. The next prime is 9991567. The reversal of 9991563 is 3651999.

9991563 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (9991559) and next prime (9991567).

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

It is not a de Polignac number, because 9991563 - 2² = 9991559 is a prime.

9991563 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (9991567) 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, 97906 + ... + 98007.

It is an arithmetic number, because the mean of its divisors is an integer number (1763226).

Almost surely, 2^9991563 is an apocalyptic number.

9991563 is a deficient number, since it is larger than the sum of its proper divisors (4114245).

9991563 is a wasteful number, since it uses less digits than its factorization.

9991563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195933.

The product of its digits is 65610, while the sum is 42.

The square root of 9991563 is about 3160.9433718433. The cubic root of 9991563 is about 215.3828620704.

The spelling of 9991563 in words is "nine million, nine hundred ninety-one thousand, five hundred sixty-three".