1643412808657 has 2 divisors, whose sum is σ = 1643412808658. Its totient is φ = 1643412808656.

The previous prime is 1643412808619. The next prime is 1643412808691. The reversal of 1643412808657 is 7568082143461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1486060959681 + 157351848976 = 1219041^2 + 396676^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1643412808657 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1643412808598 and 1643412808607.

It is not a weakly prime, because it can be changed into another prime (1643412808757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821706404328 + 821706404329.

It is an arithmetic number, because the mean of its divisors is an integer number (821706404329).

Almost surely, 2^{1643412808657} is an apocalyptic number.

It is an amenable number.

1643412808657 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643412808657 is an equidigital number, since it uses as much as digits as its factorization.

1643412808657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7741440, while the sum is 55.

The spelling of 1643412808657 in words is "one trillion, six hundred forty-three billion, four hundred twelve million, eight hundred eight thousand, six hundred fifty-seven".