243620257 has 2 divisors, whose sum is σ = 243620258. Its totient is φ = 243620256.

The previous prime is 243620249. The next prime is 243620269. The reversal of 243620257 is 752026342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 224880016 + 18740241 = 14996^2 + 4329^2 .

It is a cyclic number.

It is not a de Polignac number, because 243620257 - 2³ = 243620249 is a prime.

It is not a weakly prime, because it can be changed into another prime (243620297) 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, 121810128 + 121810129.

It is an arithmetic number, because the mean of its divisors is an integer number (121810129).

Almost surely, 2^243620257 is an apocalyptic number.

It is an amenable number.

243620257 is a deficient number, since it is larger than the sum of its proper divisors (1).

243620257 is an equidigital number, since it uses as much as digits as its factorization.

243620257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20160, while the sum is 31.

The square root of 243620257 is about 15608.3393415187. The cubic root of 243620257 is about 624.5556367810. Note that the first 3 decimals are identical.

Adding to 243620257 its reverse (752026342), we get a palindrome (995646599).

The spelling of 243620257 in words is "two hundred forty-three million, six hundred twenty thousand, two hundred fifty-seven".