8193991 has 4 divisors (see below), whose sum is σ = 8824312. Its totient is φ = 7563672.

The previous prime is 8193961. The next prime is 8194007. The reversal of 8193991 is 1993918.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 8193991 - 2¹³ = 8185799 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 (8193961) 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, 315141 + ... + 315166.

It is an arithmetic number, because the mean of its divisors is an integer number (2206078).

Almost surely, 2^8193991 is an apocalyptic number.

8193991 is a deficient number, since it is larger than the sum of its proper divisors (630321).

8193991 is a wasteful number, since it uses less digits than its factorization.

8193991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630320.

The product of its digits is 17496, while the sum is 40.

The square root of 8193991 is about 2862.5148034552. The cubic root of 8193991 is about 201.6036980588.

The spelling of 8193991 in words is "eight million, one hundred ninety-three thousand, nine hundred ninety-one".