243211421 has 2 divisors, whose sum is σ = 243211422. Its totient is φ = 243211420.

The previous prime is 243211411. The next prime is 243211427. The reversal of 243211421 is 124112342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 243204025 + 7396 = 15595^2 + 86^2 .

It is a cyclic number.

It is not a de Polignac number, because 243211421 - 2⁶ = 243211357 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 243211393 and 243211402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243211427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121605710 + 121605711.

It is an arithmetic number, because the mean of its divisors is an integer number (121605711).

Almost surely, 2^243211421 is an apocalyptic number.

It is an amenable number.

243211421 is a deficient number, since it is larger than the sum of its proper divisors (1).

243211421 is an equidigital number, since it uses as much as digits as its factorization.

243211421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 20.

The square root of 243211421 is about 15595.2371254816. The cubic root of 243211421 is about 624.2060711636.

Adding to 243211421 its reverse (124112342), we get a palindrome (367323763).

The spelling of 243211421 in words is "two hundred forty-three million, two hundred eleven thousand, four hundred twenty-one".