243369221 has 2 divisors, whose sum is σ = 243369222. Its totient is φ = 243369220.

The previous prime is 243369179. The next prime is 243369223. The reversal of 243369221 is 122963342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 234518596 + 8850625 = 15314^2 + 2975^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243369221 is a prime.

Together with 243369223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243369223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121684610 + 121684611.

It is an arithmetic number, because the mean of its divisors is an integer number (121684611).

Almost surely, 2^243369221 is an apocalyptic number.

It is an amenable number.

243369221 is a deficient number, since it is larger than the sum of its proper divisors (1).

243369221 is an equidigital number, since it uses as much as digits as its factorization.

243369221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 32.

The square root of 243369221 is about 15600.2955420723. The cubic root of 243369221 is about 624.3410407338.

The spelling of 243369221 in words is "two hundred forty-three million, three hundred sixty-nine thousand, two hundred twenty-one".