664641040 has 80 divisors (see below), whose sum is σ = 1769708160. Its totient is φ = 227404800.

The previous prime is 664641013. The next prime is 664641083. The reversal of 664641040 is 40146466.

664641040 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 664640993 and 664641011.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 368140 + ... + 369940.

It is an arithmetic number, because the mean of its divisors is an integer number (22121352).

Almost surely, 2^664641040 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 664641040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (884854080).

664641040 is an abundant number, since it is smaller than the sum of its proper divisors (1105067120).

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

664641040 is a wasteful number, since it uses less digits than its factorization.

664641040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2480 (or 2474 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 664641040 is about 25780.6330411028. The cubic root of 664641040 is about 872.6947931673.

The spelling of 664641040 in words is "six hundred sixty-four million, six hundred forty-one thousand, forty".