665543231 has 4 divisors (see below), whose sum is σ = 665682192. Its totient is φ = 665404272.

The previous prime is 665543189. The next prime is 665543233. The reversal of 665543231 is 132345566.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665543231 is a prime.

It is a super-2 number, since 2×665543231² = 885895584659838722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665543191 and 665543200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665543233) 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, 62030 + ... + 71963.

It is an arithmetic number, because the mean of its divisors is an integer number (166420548).

Almost surely, 2^665543231 is an apocalyptic number.

665543231 is a deficient number, since it is larger than the sum of its proper divisors (138961).

665543231 is a wasteful number, since it uses less digits than its factorization.

665543231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138960.

The product of its digits is 64800, while the sum is 35.

The square root of 665543231 is about 25798.1245636190. The cubic root of 665543231 is about 873.0894831139.

Adding to 665543231 its reverse (132345566), we get a palindrome (797888797).

The spelling of 665543231 in words is "six hundred sixty-five million, five hundred forty-three thousand, two hundred thirty-one".