643009 has 2 divisors, whose sum is σ = 643010. Its totient is φ = 643008.

The previous prime is 642997. The next prime is 643021. The reversal of 643009 is 900346.

It is a balanced prime because it is at equal distance from previous prime (642997) and next prime (643021).

It can be written as a sum of positive squares in only one way, i.e., 518400 + 124609 = 720^2 + 353^2 .

It is a cyclic number.

It is not a de Polignac number, because 643009 - 2⁵ = 642977 is a prime.

It is not a weakly prime, because it can be changed into another prime (643039) 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, 321504 + 321505.

It is an arithmetic number, because the mean of its divisors is an integer number (321505).

2⁶⁴³⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

643009 is a deficient number, since it is larger than the sum of its proper divisors (1).

643009 is an equidigital number, since it uses as much as digits as its factorization.

643009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 643009 is about 801.8784197121. The cubic root of 643009 is about 86.3122326188.

The spelling of 643009 in words is "six hundred forty-three thousand, nine".