16565021117 has 2 divisors, whose sum is σ = 16565021118. Its totient is φ = 16565021116.

The previous prime is 16565021003. The next prime is 16565021171. The reversal of 16565021117 is 71112056561.

Together with next prime (16565021171) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12845728921 + 3719292196 = 113339^2 + 60986^2 .

It is a cyclic number.

It is not a de Polignac number, because 16565021117 - 2¹⁴ = 16565004733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16565021197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8282510558 + 8282510559.

It is an arithmetic number, because the mean of its divisors is an integer number (8282510559).

Almost surely, 2^16565021117 is an apocalyptic number.

It is an amenable number.

16565021117 is a deficient number, since it is larger than the sum of its proper divisors (1).

16565021117 is an equidigital number, since it uses as much as digits as its factorization.

16565021117 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12600, while the sum is 35.

Adding to 16565021117 its reverse (71112056561), we get a palindrome (87677077678).

The spelling of 16565021117 in words is "sixteen billion, five hundred sixty-five million, twenty-one thousand, one hundred seventeen".