243403431421 has 2 divisors, whose sum is σ = 243403431422. Its totient is φ = 243403431420.

The previous prime is 243403431389. The next prime is 243403431437. The reversal of 243403431421 is 124134304342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129776460025 + 113626971396 = 360245^2 + 337086^2 .

It is a cyclic number.

It is not a de Polignac number, because 243403431421 - 2⁵ = 243403431389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243403431221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121701715710 + 121701715711.

It is an arithmetic number, because the mean of its divisors is an integer number (121701715711).

Almost surely, 2^243403431421 is an apocalyptic number.

It is an amenable number.

243403431421 is a deficient number, since it is larger than the sum of its proper divisors (1).

243403431421 is an equidigital number, since it uses as much as digits as its factorization.

243403431421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27648, while the sum is 31.

Adding to 243403431421 its reverse (124134304342), we get a palindrome (367537735763).

The spelling of 243403431421 in words is "two hundred forty-three billion, four hundred three million, four hundred thirty-one thousand, four hundred twenty-one".