643338253 has 2 divisors, whose sum is σ = 643338254. Its totient is φ = 643338252.

The previous prime is 643338251. The next prime is 643338299. The reversal of 643338253 is 352833346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 639735849 + 3602404 = 25293^2 + 1898^2 .

It is a cyclic number.

It is not a de Polignac number, because 643338253 - 2¹ = 643338251 is a prime.

Together with 643338251, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643338251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321669126 + 321669127.

It is an arithmetic number, because the mean of its divisors is an integer number (321669127).

Almost surely, 2^643338253 is an apocalyptic number.

It is an amenable number.

643338253 is a deficient number, since it is larger than the sum of its proper divisors (1).

643338253 is an equidigital number, since it uses as much as digits as its factorization.

643338253 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 37.

The square root of 643338253 is about 25364.1134873664. The cubic root of 643338253 is about 863.2696217533.

The spelling of 643338253 in words is "six hundred forty-three million, three hundred thirty-eight thousand, two hundred fifty-three".