7993991 has 4 divisors (see below), whose sum is σ = 7999992. Its totient is φ = 7987992.

The previous prime is 7993987. The next prime is 7994017. The reversal of 7993991 is 1993997.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 7993991 - 2² = 7993987 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 (7995991) 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, 5 + ... + 3998.

It is an arithmetic number, because the mean of its divisors is an integer number (1999998).

Almost surely, 2^7993991 is an apocalyptic number.

7993991 is a deficient number, since it is larger than the sum of its proper divisors (6001).

7993991 is a wasteful number, since it uses less digits than its factorization.

7993991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6000.

The product of its digits is 137781, while the sum is 47.

The square root of 7993991 is about 2827.3646740384. The cubic root of 7993991 is about 199.9499124572.

The spelling of 7993991 in words is "seven million, nine hundred ninety-three thousand, nine hundred ninety-one".