660005720 has 64 divisors (see below), whose sum is σ = 1631988000. Its totient is φ = 238228480.

The previous prime is 660005719. The next prime is 660005743. The reversal of 660005720 is 27500066.

It is a self number, because there is not a number n which added to its sum of digits gives 660005720.

It is a congruent number.

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, 54806 + ... + 65754.

Almost surely, 2^660005720 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 660005720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (815994000).

660005720 is an abundant number, since it is smaller than the sum of its proper divisors (971982280).

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

660005720 is a wasteful number, since it uses less digits than its factorization.

660005720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11108 (or 11104 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 660005720 is about 25690.5764824381. The cubic root of 660005720 is about 870.6612843465.

Adding to 660005720 its reverse (27500066), we get a palindrome (687505786).

The spelling of 660005720 in words is "six hundred sixty million, five thousand, seven hundred twenty".