243121300421 has 2 divisors, whose sum is σ = 243121300422. Its totient is φ = 243121300420.

The previous prime is 243121300403. The next prime is 243121300441. The reversal of 243121300421 is 124003121342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 140666253025 + 102455047396 = 375055^2 + 320086^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243121300421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243121300441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121560650210 + 121560650211.

It is an arithmetic number, because the mean of its divisors is an integer number (121560650211).

Almost surely, 2^243121300421 is an apocalyptic number.

It is an amenable number.

243121300421 is a deficient number, since it is larger than the sum of its proper divisors (1).

243121300421 is an equidigital number, since it uses as much as digits as its factorization.

243121300421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 243121300421 its reverse (124003121342), we get a palindrome (367124421763).

The spelling of 243121300421 in words is "two hundred forty-three billion, one hundred twenty-one million, three hundred thousand, four hundred twenty-one".