643279601 has 2 divisors, whose sum is σ = 643279602. Its totient is φ = 643279600.

The previous prime is 643279597. The next prime is 643279619. The reversal of 643279601 is 106972346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 560032225 + 83247376 = 23665^2 + 9124^2 .

It is a cyclic number.

It is not a de Polignac number, because 643279601 - 2² = 643279597 is a prime.

It is not a weakly prime, because it can be changed into another prime (643279621) 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, 321639800 + 321639801.

It is an arithmetic number, because the mean of its divisors is an integer number (321639801).

Almost surely, 2^643279601 is an apocalyptic number.

It is an amenable number.

643279601 is a deficient number, since it is larger than the sum of its proper divisors (1).

643279601 is an equidigital number, since it uses as much as digits as its factorization.

643279601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54432, while the sum is 38.

The square root of 643279601 is about 25362.9572605404. The cubic root of 643279601 is about 863.2433867059.

The spelling of 643279601 in words is "six hundred forty-three million, two hundred seventy-nine thousand, six hundred one".