243121254421 has 2 divisors, whose sum is σ = 243121254422. Its totient is φ = 243121254420.

The previous prime is 243121254391. The next prime is 243121254449. The reversal of 243121254421 is 124452121342.

243121254421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180273271396 + 62847983025 = 424586^2 + 250695^2 .

It is a cyclic number.

It is not a de Polignac number, because 243121254421 - 2¹³ = 243121246229 is a prime.

It is a super-2 number, since 2×243121254421² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243121254821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121560627210 + 121560627211.

It is an arithmetic number, because the mean of its divisors is an integer number (121560627211).

Almost surely, 2^243121254421 is an apocalyptic number.

It is an amenable number.

243121254421 is a deficient number, since it is larger than the sum of its proper divisors (1).

243121254421 is an equidigital number, since it uses as much as digits as its factorization.

243121254421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15360, while the sum is 31.

Adding to 243121254421 its reverse (124452121342), we get a palindrome (367573375763).

The spelling of 243121254421 in words is "two hundred forty-three billion, one hundred twenty-one million, two hundred fifty-four thousand, four hundred twenty-one".