665797567 has 4 divisors (see below), whose sum is σ = 665879896. Its totient is φ = 665715240.

The previous prime is 665797553. The next prime is 665797579. The reversal of 665797567 is 765797566.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 765797566 = 2 ⋅382898783.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665797567 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665795567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27528 + ... + 45709.

It is an arithmetic number, because the mean of its divisors is an integer number (166469974).

Almost surely, 2^665797567 is an apocalyptic number.

665797567 is a deficient number, since it is larger than the sum of its proper divisors (82329).

665797567 is an equidigital number, since it uses as much as digits as its factorization.

665797567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82328.

The product of its digits is 16669800, while the sum is 58.

The square root of 665797567 is about 25803.0534433427. The cubic root of 665797567 is about 873.2006854101.

Subtracting 665797567 from its reverse (765797566), we obtain a palindrome (99999999).

The spelling of 665797567 in words is "six hundred sixty-five million, seven hundred ninety-seven thousand, five hundred sixty-seven".