243541409 has 2 divisors, whose sum is σ = 243541410. Its totient is φ = 243541408.

The previous prime is 243541399. The next prime is 243541471. The reversal of 243541409 is 904145342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 166926400 + 76615009 = 12920^2 + 8753^2 .

It is a cyclic number.

It is not a de Polignac number, because 243541409 - 2⁴ = 243541393 is a prime.

It is a super-3 number, since 3×243541409³ (a number of 26 digits) contains 333 as substring.

It is equal to p_13344926 and since 243541409 and 13344926 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (243541499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121770704 + 121770705.

It is an arithmetic number, because the mean of its divisors is an integer number (121770705).

Almost surely, 2^243541409 is an apocalyptic number.

It is an amenable number.

243541409 is a deficient number, since it is larger than the sum of its proper divisors (1).

243541409 is an equidigital number, since it uses as much as digits as its factorization.

243541409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 243541409 is about 15605.8133078670. The cubic root of 243541409 is about 624.4882501070.

The spelling of 243541409 in words is "two hundred forty-three million, five hundred forty-one thousand, four hundred nine".