6721243920 has 480 divisors, whose sum is σ = 25478369280. Its totient is φ = 1640424960.

The previous prime is 6721243877. The next prime is 6721243927. The reversal of 6721243920 is 293421276.

6721243920 is a `hidden beast` number, since 6 + 7 + 212 + 439 + 2 + 0 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (6721243927) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 11449867 + ... + 11450453.

It is an arithmetic number, because the mean of its divisors is an integer number (53079936).

Almost surely, 2^6721243920 is an apocalyptic number.

6721243920 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 6721243920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12739184640).

6721243920 is an abundant number, since it is smaller than the sum of its proper divisors (18757125360).

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

6721243920 is a wasteful number, since it uses less digits than its factorization.

6721243920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 665 (or 647 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 6721243920 is about 81983.1929117182. The cubic root of 6721243920 is about 1887.1940221234.

The spelling of 6721243920 in words is "six billion, seven hundred twenty-one million, two hundred forty-three thousand, nine hundred twenty".