665897 has 2 divisors, whose sum is σ = 665898. Its totient is φ = 665896.

The previous prime is 665857. The next prime is 665921. The reversal of 665897 is 798566.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 502681 + 163216 = 709^2 + 404^2 .

It is a cyclic number.

It is not a de Polignac number, because 665897 - 2¹⁶ = 600361 is a prime.

It is not a weakly prime, because it can be changed into another prime (665857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332948 + 332949.

It is an arithmetic number, because the mean of its divisors is an integer number (332949).

2⁶⁶⁵⁸⁹⁷ is an apocalyptic number.

It is an amenable number.

665897 is a deficient number, since it is larger than the sum of its proper divisors (1).

665897 is an equidigital number, since it uses as much as digits as its factorization.

665897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 41.

The square root of 665897 is about 816.0251221623. The cubic root of 665897 is about 87.3244152397.

Subtracting from 665897 its sum of digits (41), we obtain a square (665856 = 816²).

The spelling of 665897 in words is "six hundred sixty-five thousand, eight hundred ninety-seven".