243421321521 has 8 divisors (see below), whose sum is σ = 370927728064. Its totient is φ = 139097898000.

The previous prime is 243421321511. The next prime is 243421321567. The reversal of 243421321521 is 125123124342.

It is a happy number.

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

It is not a de Polignac number, because 243421321521 - 2¹³ = 243421313329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243421321511) 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 7 ways as a sum of consecutive naturals, for example, 5795745730 + ... + 5795745771.

It is an arithmetic number, because the mean of its divisors is an integer number (46365966008).

Almost surely, 2^243421321521 is an apocalyptic number.

243421321521 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

243421321521 is a deficient number, since it is larger than the sum of its proper divisors (127506406543).

243421321521 is a wasteful number, since it uses less digits than its factorization.

243421321521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11591491511.

The product of its digits is 11520, while the sum is 30.

Adding to 243421321521 its reverse (125123124342), we get a palindrome (368544445863).

The spelling of 243421321521 in words is "two hundred forty-three billion, four hundred twenty-one million, three hundred twenty-one thousand, five hundred twenty-one".