1644343009 has 2 divisors, whose sum is σ = 1644343010. Its totient is φ = 1644343008.

The previous prime is 1644342989. The next prime is 1644343021. The reversal of 1644343009 is 9003434461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1235171025 + 409171984 = 35145^2 + 20228^2 .

It is a cyclic number.

It is not a de Polignac number, because 1644343009 - 2¹³ = 1644334817 is a prime.

It is a super-3 number, since 3×1644343009³ (a number of 29 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1644343079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822171504 + 822171505.

It is an arithmetic number, because the mean of its divisors is an integer number (822171505).

Almost surely, 2^1644343009 is an apocalyptic number.

It is an amenable number.

1644343009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1644343009 is an equidigital number, since it uses as much as digits as its factorization.

1644343009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 34.

The square root of 1644343009 is about 40550.4994913749. The cubic root of 1644343009 is about 1180.3137653119.

The spelling of 1644343009 in words is "one billion, six hundred forty-four million, three hundred forty-three thousand, nine".