243721297 has 2 divisors, whose sum is σ = 243721298. Its totient is φ = 243721296.

The previous prime is 243721267. The next prime is 243721301. The reversal of 243721297 is 792127342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151388416 + 92332881 = 12304^2 + 9609^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243721297 is a prime.

It is a super-2 number, since 2×243721297² = 118800141222724418, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (243721207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121860648 + 121860649.

It is an arithmetic number, because the mean of its divisors is an integer number (121860649).

Almost surely, 2^243721297 is an apocalyptic number.

It is an amenable number.

243721297 is a deficient number, since it is larger than the sum of its proper divisors (1).

243721297 is an equidigital number, since it uses as much as digits as its factorization.

243721297 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336, while the sum is 37.

The square root of 243721297 is about 15611.5757372534. The cubic root of 243721297 is about 624.6419683805.

The spelling of 243721297 in words is "two hundred forty-three million, seven hundred twenty-one thousand, two hundred ninety-seven".