1720661259389 has 2 divisors, whose sum is σ = 1720661259390. Its totient is φ = 1720661259388.

The previous prime is 1720661259337. The next prime is 1720661259397. The reversal of 1720661259389 is 9839521660271.

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., 1557229452100 + 163431807289 = 1247890^2 + 404267^2 .

It is a cyclic number.

It is not a de Polignac number, because 1720661259389 - 2¹² = 1720661255293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1720661259319) 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, 860330629694 + 860330629695.

It is an arithmetic number, because the mean of its divisors is an integer number (860330629695).

Almost surely, 2^{1720661259389} is an apocalyptic number.

It is an amenable number.

1720661259389 is a deficient number, since it is larger than the sum of its proper divisors (1).

1720661259389 is an equidigital number, since it uses as much as digits as its factorization.

1720661259389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9797760, while the sum is 59.

The spelling of 1720661259389 in words is "one trillion, seven hundred twenty billion, six hundred sixty-one million, two hundred fifty-nine thousand, three hundred eighty-nine".