6991312680 has 192 divisors, whose sum is σ = 25255825920. Its totient is φ = 1662835200.

The previous prime is 6991312667. The next prime is 6991312687. The reversal of 6991312680 is 862131996.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (6991312687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 193225 + ... + 226535.

It is an arithmetic number, because the mean of its divisors is an integer number (131540760).

Almost surely, 2^6991312680 is an apocalyptic number.

6991312680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6991312680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12627912960).

6991312680 is an abundant number, since it is smaller than the sum of its proper divisors (18264513240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6991312680 is a wasteful number, since it uses less digits than its factorization.

6991312680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33392 (or 33385 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 6991312680 is about 83614.0698686531. The cubic root of 6991312680 is about 1912.1395101660.

The spelling of 6991312680 in words is "six billion, nine hundred ninety-one million, three hundred twelve thousand, six hundred eighty".