6691449378 has 16 divisors (see below), whose sum is σ = 13391501760. Its totient is φ = 2229049296.

The previous prime is 6691449377. The next prime is 6691449379. The reversal of 6691449378 is 8739441966.

It is an interprime number because it is at equal distance from previous prime (6691449377) and next prime (6691449379).

It is not an unprimeable number, because it can be changed into a prime (6691449377) 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 7 ways as a sum of consecutive naturals, for example, 348325 + ... + 367032.

It is an arithmetic number, because the mean of its divisors is an integer number (836968860).

Almost surely, 2^6691449378 is an apocalyptic number.

6691449378 is an abundant number, since it is smaller than the sum of its proper divisors (6700052382).

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

6691449378 is a wasteful number, since it uses less digits than its factorization.

6691449378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 716921.

The product of its digits is 7838208, while the sum is 57.

The square root of 6691449378 is about 81801.2798066143. The cubic root of 6691449378 is about 1884.4013163007.

The spelling of 6691449378 in words is "six billion, six hundred ninety-one million, four hundred forty-nine thousand, three hundred seventy-eight".