1720661259397 has 2 divisors, whose sum is σ = 1720661259398. Its totient is φ = 1720661259396.

The previous prime is 1720661259389. The next prime is 1720661259403. The reversal of 1720661259397 is 7939521660271.

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., 1459145618401 + 261515640996 = 1207951^2 + 511386^2 .

It is an emirp because it is prime and its reverse (7939521660271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1720661259397 - 2³ = 1720661259389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1720661259337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860330629698 + 860330629699.

It is an arithmetic number, because the mean of its divisors is an integer number (860330629699).

Almost surely, 2^{1720661259397} is an apocalyptic number.

It is an amenable number.

1720661259397 is a deficient number, since it is larger than the sum of its proper divisors (1).

1720661259397 is an equidigital number, since it uses as much as digits as its factorization.

1720661259397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8573040, while the sum is 58.

The spelling of 1720661259397 in words is "one trillion, seven hundred twenty billion, six hundred sixty-one million, two hundred fifty-nine thousand, three hundred ninety-seven".