4243721809 has 4 divisors (see below), whose sum is σ = 4246631920. Its totient is φ = 4240811700.

The previous prime is 4243721737. The next prime is 4243721831. The reversal of 4243721809 is 9081273424.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 4243721809 - 2¹¹ = 4243719761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4243721869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1452867 + ... + 1455784.

It is an arithmetic number, because the mean of its divisors is an integer number (1061657980).

Almost surely, 2^4243721809 is an apocalyptic number.

It is an amenable number.

4243721809 is a deficient number, since it is larger than the sum of its proper divisors (2910111).

4243721809 is a wasteful number, since it uses less digits than its factorization.

4243721809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2910110.

The product of its (nonzero) digits is 96768, while the sum is 40.

The square root of 4243721809 is about 65143.8547293603. The cubic root of 4243721809 is about 1619.0079035838.

It can be divided in two parts, 42437 and 21809, that added together give a palindrome (64246).

The spelling of 4243721809 in words is "four billion, two hundred forty-three million, seven hundred twenty-one thousand, eight hundred nine".