243021005 has 4 divisors (see below), whose sum is σ = 291625212. Its totient is φ = 194416800.

The previous prime is 243020927. The next prime is 243021007. The reversal of 243021005 is 500120342.

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 96393124 + 146627881 = 9818^2 + 12109^2 .

It is not a de Polignac number, because 243021005 - 2¹² = 243016909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243021007) 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, 24302096 + ... + 24302105.

It is an arithmetic number, because the mean of its divisors is an integer number (72906303).

Almost surely, 2^243021005 is an apocalyptic number.

It is an amenable number.

243021005 is a deficient number, since it is larger than the sum of its proper divisors (48604207).

243021005 is an equidigital number, since it uses as much as digits as its factorization.

243021005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48604206.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 243021005 is about 15589.1309892502. The cubic root of 243021005 is about 624.0431267106.

Adding to 243021005 its reverse (500120342), we get a palindrome (743141347).

The spelling of 243021005 in words is "two hundred forty-three million, twenty-one thousand, five".