717891551989 has 2 divisors, whose sum is σ = 717891551990. Its totient is φ = 717891551988.

The previous prime is 717891551947. The next prime is 717891552017. The reversal of 717891551989 is 989155198717.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 717324302500 + 567249489 = 846950^2 + 23817^2 .

It is a cyclic number.

It is not a de Polignac number, because 717891551989 - 2⁹ = 717891551477 is a prime.

It is a super-2 number, since 2×717891551989² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (717891551789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 358945775994 + 358945775995.

It is an arithmetic number, because the mean of its divisors is an integer number (358945775995).

Almost surely, 2^717891551989 is an apocalyptic number.

It is an amenable number.

717891551989 is a deficient number, since it is larger than the sum of its proper divisors (1).

717891551989 is an equidigital number, since it uses as much as digits as its factorization.

717891551989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 57153600, while the sum is 70.

The spelling of 717891551989 in words is "seven hundred seventeen billion, eight hundred ninety-one million, five hundred fifty-one thousand, nine hundred eighty-nine".