243424131221 has 2 divisors, whose sum is σ = 243424131222. Its totient is φ = 243424131220.

The previous prime is 243424131191. The next prime is 243424131233. The reversal of 243424131221 is 122131424342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 204688380625 + 38735750596 = 452425^2 + 196814^2 .

It is a cyclic number.

It is not a de Polignac number, because 243424131221 - 2²² = 243419936917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243424131271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121712065610 + 121712065611.

It is an arithmetic number, because the mean of its divisors is an integer number (121712065611).

Almost surely, 2^243424131221 is an apocalyptic number.

It is an amenable number.

243424131221 is a deficient number, since it is larger than the sum of its proper divisors (1).

243424131221 is an equidigital number, since it uses as much as digits as its factorization.

243424131221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9216, while the sum is 29.

Adding to 243424131221 its reverse (122131424342), we get a palindrome (365555555563).

The spelling of 243424131221 in words is "two hundred forty-three billion, four hundred twenty-four million, one hundred thirty-one thousand, two hundred twenty-one".