665968211 has 2 divisors, whose sum is σ = 665968212. Its totient is φ = 665968210.

The previous prime is 665968201. The next prime is 665968231. The reversal of 665968211 is 112869566.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665968211 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (665968201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332984105 + 332984106.

It is an arithmetic number, because the mean of its divisors is an integer number (332984106).

Almost surely, 2^665968211 is an apocalyptic number.

665968211 is a deficient number, since it is larger than the sum of its proper divisors (1).

665968211 is an equidigital number, since it uses as much as digits as its factorization.

665968211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520, while the sum is 44.

The square root of 665968211 is about 25806.3598944136. The cubic root of 665968211 is about 873.2752795194.

The spelling of 665968211 in words is "six hundred sixty-five million, nine hundred sixty-eight thousand, two hundred eleven".