665970211 has 2 divisors, whose sum is σ = 665970212. Its totient is φ = 665970210.

The previous prime is 665970209. The next prime is 665970259. The reversal of 665970211 is 112079566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665970211 - 2¹ = 665970209 is a prime.

Together with 665970209, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (665977211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332985105 + 332985106.

It is an arithmetic number, because the mean of its divisors is an integer number (332985106).

Almost surely, 2^665970211 is an apocalyptic number.

665970211 is a deficient number, since it is larger than the sum of its proper divisors (1).

665970211 is an equidigital number, since it uses as much as digits as its factorization.

665970211 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 665970211 is about 25806.3986445223. The cubic root of 665970211 is about 873.2761537096.

The spelling of 665970211 in words is "six hundred sixty-five million, nine hundred seventy thousand, two hundred eleven".