243161321 has 16 divisors (see below), whose sum is σ = 266753424. Its totient is φ = 220299264.

The previous prime is 243161287. The next prime is 243161323. The reversal of 243161321 is 123161342.

It can be written as a sum of positive squares in 8 ways, for example, as 31866025 + 211295296 = 5645^2 + 14536^2 .

It is a cyclic number.

It is not a de Polignac number, because 243161321 - 2⁶ = 243161257 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (243161323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 243395 + ... + 244391.

It is an arithmetic number, because the mean of its divisors is an integer number (16672089).

Almost surely, 2^243161321 is an apocalyptic number.

It is an amenable number.

243161321 is a deficient number, since it is larger than the sum of its proper divisors (23592103).

243161321 is a wasteful number, since it uses less digits than its factorization.

243161321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1340.

The product of its digits is 864, while the sum is 23.

The square root of 243161321 is about 15593.6307831114. The cubic root of 243161321 is about 624.1632073984.

The spelling of 243161321 in words is "two hundred forty-three million, one hundred sixty-one thousand, three hundred twenty-one".