8399991 has 24 divisors (see below), whose sum is σ = 12033280. Its totient is φ = 5209776.

The previous prime is 8399987. The next prime is 8400011. The reversal of 8399991 is 1999938.

It is not a de Polignac number, because 8399991 - 2² = 8399987 is a prime.

8399991 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 8399991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8399191) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 106290 + ... + 106368.

Almost surely, 2^8399991 is an apocalyptic number.

8399991 is a deficient number, since it is larger than the sum of its proper divisors (3633289).

8399991 is a wasteful number, since it uses less digits than its factorization.

8399991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195 (or 172 counting only the distinct ones).

The product of its digits is 157464, while the sum is 48.

The square root of 8399991 is about 2898.2737965900. The cubic root of 8399991 is about 203.2791987632.

The spelling of 8399991 in words is "eight million, three hundred ninety-nine thousand, nine hundred ninety-one".