643800233 has 2 divisors, whose sum is σ = 643800234. Its totient is φ = 643800232.

The previous prime is 643800229. The next prime is 643800277. The reversal of 643800233 is 332008346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 569633689 + 74166544 = 23867^2 + 8612^2 .

It is a cyclic number.

It is not a de Polignac number, because 643800233 - 2² = 643800229 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643800196 and 643800205.

It is not a weakly prime, because it can be changed into another prime (643800293) 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 as a sum of consecutive naturals, namely, 321900116 + 321900117.

It is an arithmetic number, because the mean of its divisors is an integer number (321900117).

Almost surely, 2^643800233 is an apocalyptic number.

It is an amenable number.

643800233 is a deficient number, since it is larger than the sum of its proper divisors (1).

643800233 is an equidigital number, since it uses as much as digits as its factorization.

643800233 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 643800233 is about 25373.2188143326. The cubic root of 643800233 is about 863.4762097463.

Adding to 643800233 its reverse (332008346), we get a palindrome (975808579).

The spelling of 643800233 in words is "six hundred forty-three million, eight hundred thousand, two hundred thirty-three".