641040660 has 144 divisors (see below), whose sum is σ = 2107756560. Its totient is φ = 157697280.

The previous prime is 641040629. The next prime is 641040683. The reversal of 641040660 is 66040146.

It can be written as a sum of positive squares in 8 ways, for example, as 398241936 + 242798724 = 19956^2 + 15582^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 394650 + ... + 396270.

Almost surely, 2^641040660 is an apocalyptic number.

641040660 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 641040660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1053878280).

641040660 is an abundant number, since it is smaller than the sum of its proper divisors (1466715900).

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

641040660 is a wasteful number, since it uses less digits than its factorization.

641040660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1675 (or 1644 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 641040660 is about 25318.7807763328. The cubic root of 641040660 is about 862.2407134909.

The spelling of 641040660 in words is "six hundred forty-one million, forty thousand, six hundred sixty".