243328781 has 2 divisors, whose sum is σ = 243328782. Its totient is φ = 243328780.

The previous prime is 243328751. The next prime is 243328819. The reversal of 243328781 is 187823342.

It is an a-pointer prime, because the next prime (243328819) can be obtained adding 243328781 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 124322500 + 119006281 = 11150^2 + 10909^2 .

It is a cyclic number.

It is not a de Polignac number, because 243328781 - 2²⁶ = 176219917 is a prime.

It is a super-2 number, since 2×243328781² = 118417791325891922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243328741) 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, 121664390 + 121664391.

It is an arithmetic number, because the mean of its divisors is an integer number (121664391).

Almost surely, 2^243328781 is an apocalyptic number.

It is an amenable number.

243328781 is a deficient number, since it is larger than the sum of its proper divisors (1).

243328781 is an equidigital number, since it uses as much as digits as its factorization.

243328781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 38.

The square root of 243328781 is about 15598.9993589333. Note that the first 3 decimals coincide. The cubic root of 243328781 is about 624.3064571353.

The spelling of 243328781 in words is "two hundred forty-three million, three hundred twenty-eight thousand, seven hundred eighty-one".