8399209991 has 4 divisors (see below), whose sum is σ = 8413185984. Its totient is φ = 8385234000.

The previous prime is 8399209979. The next prime is 8399209997. The reversal of 8399209991 is 1999029938.

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-8399209991 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8399209991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8399209997) 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, 6987095 + ... + 6988296.

It is an arithmetic number, because the mean of its divisors is an integer number (2103296496).

Almost surely, 2^8399209991 is an apocalyptic number.

8399209991 is a deficient number, since it is larger than the sum of its proper divisors (13975993).

8399209991 is a wasteful number, since it uses less digits than its factorization.

8399209991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13975992.

The product of its (nonzero) digits is 2834352, while the sum is 59.

The square root of 8399209991 is about 91647.2039453469. The cubic root of 8399209991 is about 2032.7289844675.

The spelling of 8399209991 in words is "eight billion, three hundred ninety-nine million, two hundred nine thousand, nine hundred ninety-one".