1643644411 has 2 divisors, whose sum is σ = 1643644412. Its totient is φ = 1643644410.

The previous prime is 1643644403. The next prime is 1643644417. The reversal of 1643644411 is 1144463461.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1643644411 - 2³ = 1643644403 is a prime.

It is not a weakly prime, because it can be changed into another prime (1643644417) 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, 821822205 + 821822206.

It is an arithmetic number, because the mean of its divisors is an integer number (821822206).

Almost surely, 2^1643644411 is an apocalyptic number.

1643644411 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643644411 is an equidigital number, since it uses as much as digits as its factorization.

1643644411 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 34.

The square root of 1643644411 is about 40541.8846503218. The cubic root of 1643644411 is about 1180.1465898035.

The spelling of 1643644411 in words is "one billion, six hundred forty-three million, six hundred forty-four thousand, four hundred eleven".