2117985196909 has 2 divisors, whose sum is σ = 2117985196910. Its totient is φ = 2117985196908.

The previous prime is 2117985196841. The next prime is 2117985196913. The reversal of 2117985196909 is 9096915897112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2041669476900 + 76315720009 = 1428870^2 + 276253^2 .

It is a cyclic number.

It is not a de Polignac number, because 2117985196909 - 2¹³ = 2117985188717 is a prime.

It is a super-2 number, since 2×2117985196909² (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 (2117985196969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1058992598454 + 1058992598455.

It is an arithmetic number, because the mean of its divisors is an integer number (1058992598455).

Almost surely, 2^{2117985196909} is an apocalyptic number.

It is an amenable number.

2117985196909 is a deficient number, since it is larger than the sum of its proper divisors (1).

2117985196909 is an equidigital number, since it uses as much as digits as its factorization.

2117985196909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22044960, while the sum is 67.

The spelling of 2117985196909 in words is "two trillion, one hundred seventeen billion, nine hundred eighty-five million, one hundred ninety-six thousand, nine hundred nine".