666755213 has 2 divisors, whose sum is σ = 666755214. Its totient is φ = 666755212.

The previous prime is 666755191. The next prime is 666755251. The reversal of 666755213 is 312557666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 549292969 + 117462244 = 23437^2 + 10838^2 .

It is a cyclic number.

It is not a de Polignac number, because 666755213 - 2¹⁶ = 666689677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666755273) 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 as a sum of consecutive naturals, namely, 333377606 + 333377607.

It is an arithmetic number, because the mean of its divisors is an integer number (333377607).

Almost surely, 2^666755213 is an apocalyptic number.

It is an amenable number.

666755213 is a deficient number, since it is larger than the sum of its proper divisors (1).

666755213 is an equidigital number, since it uses as much as digits as its factorization.

666755213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 226800, while the sum is 41.

The square root of 666755213 is about 25821.6036101556. The cubic root of 666755213 is about 873.6191391976.

The spelling of 666755213 in words is "six hundred sixty-six million, seven hundred fifty-five thousand, two hundred thirteen".