665618441 has 2 divisors, whose sum is σ = 665618442. Its totient is φ = 665618440.

The previous prime is 665618399. The next prime is 665618479. The reversal of 665618441 is 144816566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 588547600 + 77070841 = 24260^2 + 8779^2 .

It is a cyclic number.

It is not a de Polignac number, because 665618441 - 2¹⁰ = 665617417 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (665618491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332809220 + 332809221.

It is an arithmetic number, because the mean of its divisors is an integer number (332809221).

Almost surely, 2^665618441 is an apocalyptic number.

It is an amenable number.

665618441 is a deficient number, since it is larger than the sum of its proper divisors (1).

665618441 is an equidigital number, since it uses as much as digits as its factorization.

665618441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 41.

The square root of 665618441 is about 25799.5821865394. The cubic root of 665618441 is about 873.1223698264.

The spelling of 665618441 in words is "six hundred sixty-five million, six hundred eighteen thousand, four hundred forty-one".