99571891 has 4 divisors (see below), whose sum is σ = 100974384. Its totient is φ = 98169400.

The previous prime is 99571883. The next prime is 99571931. The reversal of 99571891 is 19817599.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19817599 = 2543 ⋅7793.

It is a cyclic number.

It is not a de Polignac number, because 99571891 - 2³ = 99571883 is a prime.

It is a super-2 number, since 2×99571891² = 19829122954631762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99571811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 701140 + ... + 701281.

It is an arithmetic number, because the mean of its divisors is an integer number (25243596).

Almost surely, 2^99571891 is an apocalyptic number.

99571891 is a deficient number, since it is larger than the sum of its proper divisors (1402493).

99571891 is a wasteful number, since it uses less digits than its factorization.

99571891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1402492.

The product of its digits is 204120, while the sum is 49.

The square root of 99571891 is about 9978.5715911647. The cubic root of 99571891 is about 463.4955672355.

The spelling of 99571891 in words is "ninety-nine million, five hundred seventy-one thousand, eight hundred ninety-one".