6721827840 has 792 divisors, whose sum is σ = 29305097640. Its totient is φ = 1412038656.

The previous prime is 6721827823. The next prime is 6721827841. The reversal of 6721827840 is 487281276.

It can be written as a sum of positive squares in 4 ways, for example, as 955551744 + 5766276096 = 30912^2 + 75936^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6721827841) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 29352846 + ... + 29353074.

Almost surely, 2^6721827840 is an apocalyptic number.

6721827840 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 6721827840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14652548820).

6721827840 is an abundant number, since it is smaller than the sum of its proper divisors (22583269800).

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

6721827840 is a wasteful number, since it uses less digits than its factorization.

6721827840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287 (or 259 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 45.

The square root of 6721827840 is about 81986.7540521028. The cubic root of 6721827840 is about 1887.2486716514.

The spelling of 6721827840 in words is "six billion, seven hundred twenty-one million, eight hundred twenty-seven thousand, eight hundred forty".