243969665 has 4 divisors (see below), whose sum is σ = 292763604. Its totient is φ = 195175728.

The previous prime is 243969631. The next prime is 243969697. The reversal of 243969665 is 566969342.

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

It can be written as a sum of positive squares in 2 ways, for example, as 75203584 + 168766081 = 8672^2 + 12991^2 .

It is a cyclic number.

It is not a de Polignac number, because 243969665 - 2⁸ = 243969409 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 24396962 + ... + 24396971.

It is an arithmetic number, because the mean of its divisors is an integer number (73190901).

Almost surely, 2^243969665 is an apocalyptic number.

It is an amenable number.

243969665 is a deficient number, since it is larger than the sum of its proper divisors (48793939).

243969665 is an equidigital number, since it uses as much as digits as its factorization.

243969665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48793938.

The product of its digits is 2099520, while the sum is 50.

The square root of 243969665 is about 15619.5283219437. The cubic root of 243969665 is about 624.8540800678.

The spelling of 243969665 in words is "two hundred forty-three million, nine hundred sixty-nine thousand, six hundred sixty-five".