6721544388 has 72 divisors (see below), whose sum is σ = 17981919648. Its totient is φ = 1946500608.

The previous prime is 6721544383. The next prime is 6721544393. The reversal of 6721544388 is 8834451276.

It is an interprime number because it is at equal distance from previous prime (6721544383) and next prime (6721544393).

It is not an unprimeable number, because it can be changed into a prime (6721544383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 63006 + ... + 131957.

It is an arithmetic number, because the mean of its divisors is an integer number (249748884).

Almost surely, 2^6721544388 is an apocalyptic number.

6721544388 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

6721544388 is an abundant number, since it is smaller than the sum of its proper divisors (11260375260).

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

6721544388 is a wasteful number, since it uses less digits than its factorization.

6721544388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195013 (or 194998 counting only the distinct ones).

The product of its digits is 1290240, while the sum is 48.

The square root of 6721544388 is about 81985.0253887867. The cubic root of 6721544388 is about 1887.2221435530. Note that the first 3 decimals are identical.

The spelling of 6721544388 in words is "six billion, seven hundred twenty-one million, five hundred forty-four thousand, three hundred eighty-eight".