665066531 has 4 divisors (see below), whose sum is σ = 665286864. Its totient is φ = 664846200.

The previous prime is 665066491. The next prime is 665066539. The reversal of 665066531 is 135660566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 135660566 = 2 ⋅67830283.

It is a cyclic number.

It is not a de Polignac number, because 665066531 - 2²² = 660872227 is a prime.

It is a super-2 number, since 2×665066531² = 884626981312747922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665066539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105575 + ... + 111696.

It is an arithmetic number, because the mean of its divisors is an integer number (166321716).

Almost surely, 2^665066531 is an apocalyptic number.

665066531 is a deficient number, since it is larger than the sum of its proper divisors (220333).

665066531 is a wasteful number, since it uses less digits than its factorization.

665066531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220332.

The product of its (nonzero) digits is 97200, while the sum is 38.

The square root of 665066531 is about 25788.8838649524. The cubic root of 665066531 is about 872.8809811735.

It can be divided in two parts, 66506 and 6531, that added together give a palindrome (73037).

The spelling of 665066531 in words is "six hundred sixty-five million, sixty-six thousand, five hundred thirty-one".