6991159 has 4 divisors (see below), whose sum is σ = 7989904. Its totient is φ = 5992416.

The previous prime is 6991147. The next prime is 6991253. The reversal of 6991159 is 9511996.

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 6991159 - 2¹¹ = 6989111 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 (6991129) 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, 499362 + ... + 499375.

It is an arithmetic number, because the mean of its divisors is an integer number (1997476).

Almost surely, 2^6991159 is an apocalyptic number.

6991159 is a deficient number, since it is larger than the sum of its proper divisors (998745).

6991159 is an equidigital number, since it uses as much as digits as its factorization.

6991159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 998744.

The product of its digits is 21870, while the sum is 40.

The square root of 6991159 is about 2644.0799912257. The cubic root of 6991159 is about 191.2125499457.

The spelling of 6991159 in words is "six million, nine hundred ninety-one thousand, one hundred fifty-nine".