665506539 has 12 divisors (see below), whose sum is σ = 961606672. Its totient is φ = 443523600.

The previous prime is 665506487. The next prime is 665506549. The reversal of 665506539 is 935605566.

665506539 is a `hidden beast` number, since 6 + 6 + 550 + 65 + 39 = 666.

It is not a de Polignac number, because 665506539 - 2²¹ = 663409387 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665506494 and 665506503.

It is not an unprimeable number, because it can be changed into a prime (665506549) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21069 + ... + 42129.

Almost surely, 2^665506539 is an apocalyptic number.

665506539 is a deficient number, since it is larger than the sum of its proper divisors (296100133).

665506539 is a wasteful number, since it uses less digits than its factorization.

665506539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24578 (or 24575 counting only the distinct ones).

The product of its (nonzero) digits is 729000, while the sum is 45.

The square root of 665506539 is about 25797.4134168525. The cubic root of 665506539 is about 873.0734380815.

The spelling of 665506539 in words is "six hundred sixty-five million, five hundred six thousand, five hundred thirty-nine".