666573361 has 2 divisors, whose sum is σ = 666573362. Its totient is φ = 666573360.

The previous prime is 666573359. The next prime is 666573431. The reversal of 666573361 is 163375666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 451775025 + 214798336 = 21255^2 + 14656^2 .

It is a cyclic number.

It is not a de Polignac number, because 666573361 - 2¹ = 666573359 is a prime.

Together with 666573359, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (666573311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333286680 + 333286681.

It is an arithmetic number, because the mean of its divisors is an integer number (333286681).

Almost surely, 2^666573361 is an apocalyptic number.

It is an amenable number.

666573361 is a deficient number, since it is larger than the sum of its proper divisors (1).

666573361 is an equidigital number, since it uses as much as digits as its factorization.

666573361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 408240, while the sum is 43.

The square root of 666573361 is about 25818.0820550249. The cubic root of 666573361 is about 873.5397078310.

The spelling of 666573361 in words is "six hundred sixty-six million, five hundred seventy-three thousand, three hundred sixty-one".