6440904660 has 48 divisors (see below), whose sum is σ = 18045619200. Its totient is φ = 1716518784.

The previous prime is 6440904649. The next prime is 6440904667. The reversal of 6440904660 is 664090446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440904667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67981 + ... + 132299.

It is an arithmetic number, because the mean of its divisors is an integer number (375950400).

Almost surely, 2^6440904660 is an apocalyptic number.

6440904660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6440904660 is an abundant number, since it is smaller than the sum of its proper divisors (11604714540).

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

6440904660 is a wasteful number, since it uses less digits than its factorization.

6440904660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66000 (or 65998 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 39.

The square root of 6440904660 is about 80255.2469312755. The cubic root of 6440904660 is about 1860.5826074089.

The spelling of 6440904660 in words is "six billion, four hundred forty million, nine hundred four thousand, six hundred sixty".