7998991 has 32 divisors (see below), whose sum is σ = 10999296. Its totient is φ = 5616000.

The previous prime is 7998979. The next prime is 7999051. The reversal of 7998991 is 1998997.

It is not a de Polignac number, because 7998991 - 2⁷ = 7998863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7998941) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 60996 + ... + 61126.

It is an arithmetic number, because the mean of its divisors is an integer number (343728).

Almost surely, 2^7998991 is an apocalyptic number.

7998991 is a deficient number, since it is larger than the sum of its proper divisors (3000305).

7998991 is a wasteful number, since it uses less digits than its factorization.

7998991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223.

The product of its digits is 367416, while the sum is 52.

The square root of 7998991 is about 2828.2487514361. The cubic root of 7998991 is about 199.9915913131.

The spelling of 7998991 in words is "seven million, nine hundred ninety-eight thousand, nine hundred ninety-one".