660666620 has 72 divisors (see below), whose sum is σ = 1458319632. Its totient is φ = 251274240.

The previous prime is 660666593. The next prime is 660666641. The reversal of 660666620 is 26666066.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 1445432 + ... + 1445888.

Almost surely, 2^660666620 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 660666620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (729159816).

660666620 is an abundant number, since it is smaller than the sum of its proper divisors (797653012).

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

660666620 is a wasteful number, since it uses less digits than its factorization.

660666620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 591 (or 548 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 38.

The square root of 660666620 is about 25703.4359570856. The cubic root of 660666620 is about 870.9518010626.

The spelling of 660666620 in words is "six hundred sixty million, six hundred sixty-six thousand, six hundred twenty".