243367721 has 2 divisors, whose sum is σ = 243367722. Its totient is φ = 243367720.

The previous prime is 243367697. The next prime is 243367723. The reversal of 243367721 is 127763342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 196308121 + 47059600 = 14011^2 + 6860^2 .

It is a cyclic number.

It is not a de Polignac number, because 243367721 - 2¹⁴ = 243351337 is a prime.

Together with 243367723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (243367723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121683860 + 121683861.

It is an arithmetic number, because the mean of its divisors is an integer number (121683861).

Almost surely, 2^243367721 is an apocalyptic number.

It is an amenable number.

243367721 is a deficient number, since it is larger than the sum of its proper divisors (1).

243367721 is an equidigital number, since it uses as much as digits as its factorization.

243367721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336, while the sum is 35.

The square root of 243367721 is about 15600.2474659859. The cubic root of 243367721 is about 624.3397580278.

The spelling of 243367721 in words is "two hundred forty-three million, three hundred sixty-seven thousand, seven hundred twenty-one".