1643809188389 has 2 divisors, whose sum is σ = 1643809188390. Its totient is φ = 1643809188388.

The previous prime is 1643809188379. The next prime is 1643809188391. The reversal of 1643809188389 is 9838819083461.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1007032320100 + 636776868289 = 1003510^2 + 797983^2 .

It is a cyclic number.

It is not a de Polignac number, because 1643809188389 - 2¹² = 1643809184293 is a prime.

Together with 1643809188391, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1643809188379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821904594194 + 821904594195.

It is an arithmetic number, because the mean of its divisors is an integer number (821904594195).

Almost surely, 2^{1643809188389} is an apocalyptic number.

It is an amenable number.

1643809188389 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643809188389 is an equidigital number, since it uses as much as digits as its factorization.

1643809188389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 71663616, while the sum is 68.

The spelling of 1643809188389 in words is "one trillion, six hundred forty-three billion, eight hundred nine million, one hundred eighty-eight thousand, three hundred eighty-nine".