666405653 has 2 divisors, whose sum is σ = 666405654. Its totient is φ = 666405652.

The previous prime is 666405643. The next prime is 666405671. The reversal of 666405653 is 356504666.

It is a happy number.

666405653 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 580713604 + 85692049 = 24098^2 + 9257^2 .

It is a cyclic number.

It is not a de Polignac number, because 666405653 - 2⁴ = 666405637 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 666405653.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666405613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333202826 + 333202827.

It is an arithmetic number, because the mean of its divisors is an integer number (333202827).

Almost surely, 2^666405653 is an apocalyptic number.

It is an amenable number.

666405653 is a deficient number, since it is larger than the sum of its proper divisors (1).

666405653 is an equidigital number, since it uses as much as digits as its factorization.

666405653 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 388800, while the sum is 41.

The square root of 666405653 is about 25814.8339719627. The cubic root of 666405653 is about 873.4664416341.

The spelling of 666405653 in words is "six hundred sixty-six million, four hundred five thousand, six hundred fifty-three".