1720505386849 has 2 divisors, whose sum is σ = 1720505386850. Its totient is φ = 1720505386848.

The previous prime is 1720505386837. The next prime is 1720505386909. The reversal of 1720505386849 is 9486835050271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1527251072400 + 193254314449 = 1235820^2 + 439607^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1720505386849 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1720505386793 and 1720505386802.

It is not a weakly prime, because it can be changed into another prime (1720505381849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860252693424 + 860252693425.

It is an arithmetic number, because the mean of its divisors is an integer number (860252693425).

It is a 1-persistent number, because it is pandigital, but 2⋅1720505386849 = 3441010773698 is not.

Almost surely, 2^{1720505386849} is an apocalyptic number.

It is an amenable number.

1720505386849 is a deficient number, since it is larger than the sum of its proper divisors (1).

1720505386849 is an equidigital number, since it uses as much as digits as its factorization.

1720505386849 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14515200, while the sum is 58.

The spelling of 1720505386849 in words is "one trillion, seven hundred twenty billion, five hundred five million, three hundred eighty-six thousand, eight hundred forty-nine".