6821426664 has 640 divisors, whose sum is σ = 24149664000. Its totient is φ = 1773674496.

The previous prime is 6821426621. The next prime is 6821426669. The reversal of 6821426664 is 4666241286.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (6821426669) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 62581842 + ... + 62581950.

It is an arithmetic number, because the mean of its divisors is an integer number (37733850).

Almost surely, 2^6821426664 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 6821426664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12074832000).

6821426664 is an abundant number, since it is smaller than the sum of its proper divisors (17328237336).

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

6821426664 is a wasteful number, since it uses less digits than its factorization.

6821426664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 186 counting only the distinct ones).

The product of its digits is 663552, while the sum is 45.

The square root of 6821426664 is about 82591.9285644790. The cubic root of 6821426664 is about 1896.5242701765.

The spelling of 6821426664 in words is "six billion, eight hundred twenty-one million, four hundred twenty-six thousand, six hundred sixty-four".