666660520 has 32 divisors (see below), whose sum is σ = 1565205120. Its totient is φ = 255069760.

The previous prime is 666660473. The next prime is 666660523. The reversal of 666660520 is 25066666.

It is a self number, because there is not a number n which added to its sum of digits gives 666660520.

It is not an unprimeable number, because it can be changed into a prime (666660523) 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, 361396 + ... + 363235.

It is an arithmetic number, because the mean of its divisors is an integer number (48912660).

Almost surely, 2^666660520 is an apocalyptic number.

It is an amenable number.

666660520 is an abundant number, since it is smaller than the sum of its proper divisors (898544600).

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

666660520 is a wasteful number, since it uses less digits than its factorization.

666660520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724665 (or 724661 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 666660520 is about 25819.7699447536. The cubic root of 666660520 is about 873.5777799241.

The spelling of 666660520 in words is "six hundred sixty-six million, six hundred sixty thousand, five hundred twenty".