243198421 has 2 divisors, whose sum is σ = 243198422. Its totient is φ = 243198420.

The previous prime is 243198407. The next prime is 243198479. The reversal of 243198421 is 124891342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 242580625 + 617796 = 15575^2 + 786^2 .

It is a cyclic number.

It is not a de Polignac number, because 243198421 - 2²¹ = 241101269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243198401) 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, 121599210 + 121599211.

It is an arithmetic number, because the mean of its divisors is an integer number (121599211).

Almost surely, 2^243198421 is an apocalyptic number.

It is an amenable number.

243198421 is a deficient number, since it is larger than the sum of its proper divisors (1).

243198421 is an equidigital number, since it uses as much as digits as its factorization.

243198421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 34.

The square root of 243198421 is about 15594.8203259929. The cubic root of 243198421 is about 624.1949493949.

The spelling of 243198421 in words is "two hundred forty-three million, one hundred ninety-eight thousand, four hundred twenty-one".