243665406605 has 8 divisors (see below), whose sum is σ = 292875487512. Its totient is φ = 194614325568.

The previous prime is 243665406601. The next prime is 243665406613. The reversal of 243665406605 is 506604566342.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 15060934729 + 228604471876 = 122723^2 + 478126^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 243665406605 - 2² = 243665406601 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 243665406605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243665406601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39746594 + ... + 39752723.

It is an arithmetic number, because the mean of its divisors is an integer number (36609435939).

Almost surely, 2^243665406605 is an apocalyptic number.

It is an amenable number.

243665406605 is a deficient number, since it is larger than the sum of its proper divisors (49210080907).

243665406605 is an equidigital number, since it uses as much as digits as its factorization.

243665406605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79499935.

The product of its (nonzero) digits is 3110400, while the sum is 47.

The spelling of 243665406605 in words is "two hundred forty-three billion, six hundred sixty-five million, four hundred six thousand, six hundred five".