665660443 has 20 divisors (see below), whose sum is σ = 791360928. Its totient is φ = 559693680.

The previous prime is 665660441. The next prime is 665660453. The reversal of 665660443 is 344066566.

It is not a de Polignac number, because 665660443 - 2¹ = 665660441 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665660396 and 665660405.

It is not an unprimeable number, because it can be changed into a prime (665660441) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 124638 + ... + 129868.

Almost surely, 2^665660443 is an apocalyptic number.

665660443 is a deficient number, since it is larger than the sum of its proper divisors (125700485).

665660443 is an frugal number, since it uses more digits than its factorization.

665660443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5312 (or 5291 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 40.

The square root of 665660443 is about 25800.3961791287. The cubic root of 665660443 is about 873.1407347595.

The spelling of 665660443 in words is "six hundred sixty-five million, six hundred sixty thousand, four hundred forty-three".