642817009 has 2 divisors, whose sum is σ = 642817010. Its totient is φ = 642817008.

The previous prime is 642817001. The next prime is 642817013. The reversal of 642817009 is 900718246.

642817009 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 620159409 + 22657600 = 24903^2 + 4760^2 .

It is a cyclic number.

It is not a de Polignac number, because 642817009 - 2³ = 642817001 is a prime.

It is not a weakly prime, because it can be changed into another prime (642817001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321408504 + 321408505.

It is an arithmetic number, because the mean of its divisors is an integer number (321408505).

Almost surely, 2^642817009 is an apocalyptic number.

It is an amenable number.

642817009 is a deficient number, since it is larger than the sum of its proper divisors (1).

642817009 is an equidigital number, since it uses as much as digits as its factorization.

642817009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 642817009 is about 25353.8361791663. The cubic root of 642817009 is about 863.0364133340.

The spelling of 642817009 in words is "six hundred forty-two million, eight hundred seventeen thousand, nine".