243998945 has 4 divisors (see below), whose sum is σ = 292798740. Its totient is φ = 195199152.

The previous prime is 243998933. The next prime is 243998947. The reversal of 243998945 is 549899342.

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 138956944 + 105042001 = 11788^2 + 10249^2 .

It is a cyclic number.

It is not a de Polignac number, because 243998945 - 2²⁰ = 242950369 is a prime.

It is a super-2 number, since 2×243998945² = 119070970322226050, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (243998947) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24399890 + ... + 24399899.

It is an arithmetic number, because the mean of its divisors is an integer number (73199685).

Almost surely, 2^243998945 is an apocalyptic number.

It is an amenable number.

243998945 is a deficient number, since it is larger than the sum of its proper divisors (48799795).

243998945 is an equidigital number, since it uses as much as digits as its factorization.

243998945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48799794.

The product of its digits is 2799360, while the sum is 53.

The square root of 243998945 is about 15620.4655820497. The cubic root of 243998945 is about 624.8790763388.

The spelling of 243998945 in words is "two hundred forty-three million, nine hundred ninety-eight thousand, nine hundred forty-five".