6721505280 has 768 divisors, whose sum is σ = 28682035200. Its totient is φ = 1459814400.

The previous prime is 6721505279. The next prime is 6721505291. The reversal of 6721505280 is 825051276.

It is a happy number.

6721505280 is a `hidden beast` number, since 6 + 72 + 1 + 505 + 2 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (768).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 44513205 + ... + 44513355.

It is an arithmetic number, because the mean of its divisors is an integer number (37346400).

Almost surely, 2^6721505280 is an apocalyptic number.

6721505280 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 6721505280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14341017600).

6721505280 is an abundant number, since it is smaller than the sum of its proper divisors (21960529920).

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

6721505280 is a wasteful number, since it uses less digits than its factorization.

6721505280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The square root of 6721505280 is about 81984.7868814697. The cubic root of 6721505280 is about 1887.2184834008.

The spelling of 6721505280 in words is "six billion, seven hundred twenty-one million, five hundred five thousand, two hundred eighty".