1643664134591 has 2 divisors, whose sum is σ = 1643664134592. Its totient is φ = 1643664134590.

The previous prime is 1643664134549. The next prime is 1643664134647. The reversal of 1643664134591 is 1954314663461.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1643664134591 - 2²² = 1643659940287 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1643664134191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821832067295 + 821832067296.

It is an arithmetic number, because the mean of its divisors is an integer number (821832067296).

Almost surely, 2^{1643664134591} is an apocalyptic number.

1643664134591 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643664134591 is an equidigital number, since it uses as much as digits as its factorization.

1643664134591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5598720, while the sum is 53.

The spelling of 1643664134591 in words is "one trillion, six hundred forty-three billion, six hundred sixty-four million, one hundred thirty-four thousand, five hundred ninety-one".