666665650 has 48 divisors (see below), whose sum is σ = 1431247680. Its totient is φ = 226296000.

The previous prime is 666665639. The next prime is 666665651. The reversal of 666665650 is 56566666.

666665650 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 666665650.

It is not an unprimeable number, because it can be changed into a prime (666665651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25921 + ... + 44779.

It is an arithmetic number, because the mean of its divisors is an integer number (29817660).

Almost surely, 2^666665650 is an apocalyptic number.

666665650 is an abundant number, since it is smaller than the sum of its proper divisors (764582030).

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

666665650 is a wasteful number, since it uses less digits than its factorization.

666665650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18979 (or 18974 counting only the distinct ones).

The product of its (nonzero) digits is 1166400, while the sum is 46.

The square root of 666665650 is about 25819.8692870433. The cubic root of 666665650 is about 873.5800206660.

The spelling of 666665650 in words is "six hundred sixty-six million, six hundred sixty-five thousand, six hundred fifty".