665544617 has 2 divisors, whose sum is σ = 665544618. Its totient is φ = 665544616.

The previous prime is 665544571. The next prime is 665544619. The reversal of 665544617 is 716445566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 543309481 + 122235136 = 23309^2 + 11056^2 .

It is a cyclic number.

It is not a de Polignac number, because 665544617 - 2⁶ = 665544553 is a prime.

Together with 665544619, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (665544619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332772308 + 332772309.

It is an arithmetic number, because the mean of its divisors is an integer number (332772309).

Almost surely, 2^665544617 is an apocalyptic number.

It is an amenable number.

665544617 is a deficient number, since it is larger than the sum of its proper divisors (1).

665544617 is an equidigital number, since it uses as much as digits as its factorization.

665544617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 604800, while the sum is 44.

The square root of 665544617 is about 25798.1514260228. The cubic root of 665544617 is about 873.0900891858.

The spelling of 665544617 in words is "six hundred sixty-five million, five hundred forty-four thousand, six hundred seventeen".