6821264 has 40 divisors (see below), whose sum is σ = 13953720. Its totient is φ = 3225600.

The previous prime is 6821263. The next prime is 6821281. The reversal of 6821264 is 4621286.

It can be written as a sum of positive squares in 4 ways, for example, as 369664 + 6451600 = 608^2 + 2540^2 .

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6821261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28184 + ... + 28424.

It is an arithmetic number, because the mean of its divisors is an integer number (348843).

Almost surely, 2^6821264 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6821264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6976860).

6821264 is an abundant number, since it is smaller than the sum of its proper divisors (7132456).

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

6821264 is a wasteful number, since it uses less digits than its factorization.

6821264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339 (or 333 counting only the distinct ones).

The product of its digits is 4608, while the sum is 29.

The square root of 6821264 is about 2611.7549655356. The cubic root of 6821264 is about 189.6509195193.

The spelling of 6821264 in words is "six million, eight hundred twenty-one thousand, two hundred sixty-four".