1643664134549 has 2 divisors, whose sum is σ = 1643664134550. Its totient is φ = 1643664134548.

The previous prime is 1643664134507. The next prime is 1643664134591. The reversal of 1643664134549 is 9454314663461.

It is a balanced prime because it is at equal distance from previous prime (1643664134507) and next prime (1643664134591).

It can be written as a sum of positive squares in only one way, i.e., 1408553580625 + 235110553924 = 1186825^2 + 484882^2 .

It is a cyclic number.

It is not a de Polignac number, because 1643664134549 - 2²⁰ = 1643663085973 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1643664134494 and 1643664134503.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1643664134449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821832067274 + 821832067275.

It is an arithmetic number, because the mean of its divisors is an integer number (821832067275).

Almost surely, 2^{1643664134549} is an apocalyptic number.

It is an amenable number.

1643664134549 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643664134549 is an equidigital number, since it uses as much as digits as its factorization.

1643664134549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22394880, while the sum is 56.

The spelling of 1643664134549 in words is "one trillion, six hundred forty-three billion, six hundred sixty-four million, one hundred thirty-four thousand, five hundred forty-nine".