9998888591 has 4 divisors (see below), whose sum is σ = 10002688752. Its totient is φ = 9995088432.

The previous prime is 9998888563. The next prime is 9998888659. The reversal of 9998888591 is 1958888999.

9998888591 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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9998888591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9998888531) 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, 1896131 + ... + 1901396.

It is an arithmetic number, because the mean of its divisors is an integer number (2500672188).

Almost surely, 2^9998888591 is an apocalyptic number.

9998888591 is a deficient number, since it is larger than the sum of its proper divisors (3800161).

9998888591 is a wasteful number, since it uses less digits than its factorization.

9998888591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3800160.

The product of its digits is 134369280, while the sum is 74.

The square root of 9998888591 is about 99994.4428005877. The cubic root of 9998888591 is about 2154.3548718046.

The spelling of 9998888591 in words is "nine billion, nine hundred ninety-eight million, eight hundred eighty-eight thousand, five hundred ninety-one".