660556720 has 40 divisors (see below), whose sum is σ = 1537999776. Its totient is φ = 263843328.

The previous prime is 660556697. The next prime is 660556723. The reversal of 660556720 is 27655066.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 660556720.

It is not an unprimeable number, because it can be changed into a prime (660556723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53884 + ... + 64996.

Almost surely, 2^660556720 is an apocalyptic number.

It is an amenable number.

660556720 is an abundant number, since it is smaller than the sum of its proper divisors (877443056).

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

660556720 is a wasteful number, since it uses less digits than its factorization.

660556720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11869 (or 11863 counting only the distinct ones).

The product of its (nonzero) digits is 75600, while the sum is 37.

The square root of 660556720 is about 25701.2980216953. The cubic root of 660556720 is about 870.9035049386.

The spelling of 660556720 in words is "six hundred sixty million, five hundred fifty-six thousand, seven hundred twenty".