243021421 has 8 divisors (see below), whose sum is σ = 251602200. Its totient is φ = 234454080.

The previous prime is 243021403. The next prime is 243021451. The reversal of 243021421 is 124120342.

It can be written as a sum of positive squares in 4 ways, for example, as 90992521 + 152028900 = 9539^2 + 12330^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 243021421 - 2²⁷ = 108803693 is a prime.

It is a super-2 number, since 2×243021421² = 118118822129718482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243021451) 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, 45891 + ... + 50911.

It is an arithmetic number, because the mean of its divisors is an integer number (31450275).

Almost surely, 2^243021421 is an apocalyptic number.

It is an amenable number.

243021421 is a deficient number, since it is larger than the sum of its proper divisors (8580779).

243021421 is a wasteful number, since it uses less digits than its factorization.

243021421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6719.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 243021421 is about 15589.1443318740. The cubic root of 243021421 is about 624.0434827865.

Adding to 243021421 its reverse (124120342), we get a palindrome (367141763).

The spelling of 243021421 in words is "two hundred forty-three million, twenty-one thousand, four hundred twenty-one".