8399925991 has 4 divisors (see below), whose sum is σ = 8400785472. Its totient is φ = 8399066512.

The previous prime is 8399925971. The next prime is 8399926001. The reversal of 8399925991 is 1995299938.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1995299938 = 2 ⋅997649969.

It is a cyclic number.

It is not a de Polignac number, because 8399925991 - 2¹⁵ = 8399893223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8399925901) 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, 414910 + ... + 434683.

It is an arithmetic number, because the mean of its divisors is an integer number (2100196368).

Almost surely, 2^8399925991 is an apocalyptic number.

8399925991 is a deficient number, since it is larger than the sum of its proper divisors (859481).

8399925991 is an equidigital number, since it uses as much as digits as its factorization.

8399925991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 859480.

The product of its digits is 14171760, while the sum is 64.

The square root of 8399925991 is about 91651.1101460315. The cubic root of 8399925991 is about 2032.7867435742.

The spelling of 8399925991 in words is "eight billion, three hundred ninety-nine million, nine hundred twenty-five thousand, nine hundred ninety-one".