99571809 has 4 divisors (see below), whose sum is σ = 132762416. Its totient is φ = 66381204.

The previous prime is 99571753. The next prime is 99571811. The reversal of 99571809 is 90817599.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-99571809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99571009) 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, 16595299 + ... + 16595304.

It is an arithmetic number, because the mean of its divisors is an integer number (33190604).

Almost surely, 2^99571809 is an apocalyptic number.

It is an amenable number.

99571809 is a deficient number, since it is larger than the sum of its proper divisors (33190607).

99571809 is a wasteful number, since it uses less digits than its factorization.

99571809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33190606.

The product of its (nonzero) digits is 204120, while the sum is 48.

The square root of 99571809 is about 9978.5674823594. The cubic root of 99571809 is about 463.4954400020.

The spelling of 99571809 in words is "ninety-nine million, five hundred seventy-one thousand, eight hundred nine".