999849809 has 4 divisors (see below), whose sum is σ = 1142685504. Its totient is φ = 857014116.

The previous prime is 999849689. The next prime is 999849811. The reversal of 999849809 is 908948999.

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 not a de Polignac number, because 999849809 - 2⁸ = 999849553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999849839) 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, 71417837 + ... + 71417850.

It is an arithmetic number, because the mean of its divisors is an integer number (285671376).

Almost surely, 2^999849809 is an apocalyptic number.

It is an amenable number.

999849809 is a deficient number, since it is larger than the sum of its proper divisors (142835695).

999849809 is a wasteful number, since it uses less digits than its factorization.

999849809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142835694.

The product of its (nonzero) digits is 15116544, while the sum is 65.

The square root of 999849809 is about 31620.4017842911. The cubic root of 999849809 is about 999.9499338268.

The spelling of 999849809 in words is "nine hundred ninety-nine million, eight hundred forty-nine thousand, eight hundred nine".