6991143256 has 8 divisors (see below), whose sum is σ = 13108393620. Its totient is φ = 3495571624.

The previous prime is 6991143253. The next prime is 6991143277. The reversal of 6991143256 is 6523411996.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6991143251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 436946446 + ... + 436946461.

Almost surely, 2^6991143256 is an apocalyptic number.

It is an amenable number.

6991143256 is a deficient number, since it is larger than the sum of its proper divisors (6117250364).

6991143256 is a wasteful number, since it uses less digits than its factorization.

6991143256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 873892913 (or 873892909 counting only the distinct ones).

The product of its digits is 349920, while the sum is 46.

The square root of 6991143256 is about 83613.0567315895. The cubic root of 6991143256 is about 1912.1240640948.

The spelling of 6991143256 in words is "six billion, nine hundred ninety-one million, one hundred forty-three thousand, two hundred fifty-six".