720666 has 12 divisors (see below), whose sum is σ = 1561482. Its totient is φ = 240216.

The previous prime is 720661. The next prime is 720677. The reversal of 720666 is 666027.

It can be written as a sum of positive squares in only one way, i.e., 531441 + 189225 = 729^2 + 435^2 .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 720666.

It is not an unprimeable number, because it can be changed into a prime (720661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 20001 + ... + 20036.

2⁷²⁰⁶⁶⁶ is an apocalyptic number.

720666 is an abundant number, since it is smaller than the sum of its proper divisors (840816).

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

720666 is a wasteful number, since it uses less digits than its factorization.

720666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40045 (or 40042 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 27.

The square root of 720666 is about 848.9204909766. The cubic root of 720666 is about 89.6557217439.

The spelling of 720666 in words is "seven hundred twenty thousand, six hundred sixty-six".