243321409 has 2 divisors, whose sum is σ = 243321410. Its totient is φ = 243321408.

The previous prime is 243321401. The next prime is 243321443. The reversal of 243321409 is 904123342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 182169009 + 61152400 = 13497^2 + 7820^2 .

It is a cyclic number.

It is not a de Polignac number, because 243321409 - 2³ = 243321401 is a prime.

It is not a weakly prime, because it can be changed into another prime (243321401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121660704 + 121660705.

It is an arithmetic number, because the mean of its divisors is an integer number (121660705).

Almost surely, 2^243321409 is an apocalyptic number.

It is an amenable number.

243321409 is a deficient number, since it is larger than the sum of its proper divisors (1).

243321409 is an equidigital number, since it uses as much as digits as its factorization.

243321409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 243321409 is about 15598.7630599352. The cubic root of 243321409 is about 624.3001523136.

The spelling of 243321409 in words is "two hundred forty-three million, three hundred twenty-one thousand, four hundred nine".