6643554064 has 135 divisors (see below), whose sum is σ = 15566738133. Its totient is φ = 2738668800.

The previous prime is 6643554061. The next prime is 6643554077. The reversal of 6643554064 is 4604553466.

The square root of 6643554064 is 81508.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 320123664 + 6323430400 = 17892^2 + 79520^2 .

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6643554064.

It is not an unprimeable number, because it can be changed into a prime (6643554061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 93571149 + ... + 93571219.

Almost surely, 2^6643554064 is an apocalyptic number.

6643554064 is the 81508-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6643554064

6643554064 is an abundant number, since it is smaller than the sum of its proper divisors (8923184069).

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

6643554064 is an equidigital number, since it uses as much as digits as its factorization.

6643554064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246 (or 121 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 43.

The cubic root of 6643554064 is about 1879.8945602552.

The spelling of 6643554064 in words is "six billion, six hundred forty-three million, five hundred fifty-four thousand, sixty-four".