641440064 has 14 divisors (see below), whose sum is σ = 1272857754. Its totient is φ = 320720000.

The previous prime is 641440061. The next prime is 641440109. The reversal of 641440064 is 460044146.

It can be written as a sum of positive squares in only one way, i.e., 549433600 + 92006464 = 23440^2 + 9592^2 .

It is a super-2 number, since 2×641440064² = 822890711408648192, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641440061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5011187 + ... + 5011314.

It is an arithmetic number, because the mean of its divisors is an integer number (90918411).

Almost surely, 2^641440064 is an apocalyptic number.

641440064 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

641440064 is a deficient number, since it is larger than the sum of its proper divisors (631417690).

641440064 is a wasteful number, since it uses less digits than its factorization.

641440064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10022513 (or 10022503 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 29.

The square root of 641440064 is about 25326.6670527332. The cubic root of 641440064 is about 862.4197509598.

The spelling of 641440064 in words is "six hundred forty-one million, four hundred forty thousand, sixty-four".