16616622116581 has 2 divisors, whose sum is σ = 16616622116582. Its totient is φ = 16616622116580.

The previous prime is 16616622116557. The next prime is 16616622116609. The reversal of 16616622116581 is 18561122661661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14910487188100 + 1706134928481 = 3861410^2 + 1306191^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16616622116581 is a prime.

It is a super-2 number, since 2×16616622116581² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16616622816581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8308311058290 + 8308311058291.

It is an arithmetic number, because the mean of its divisors is an integer number (8308311058291).

Almost surely, 2^{16616622116581} is an apocalyptic number.

It is an amenable number.

16616622116581 is a deficient number, since it is larger than the sum of its proper divisors (1).

16616622116581 is an equidigital number, since it uses as much as digits as its factorization.

16616622116581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1244160, while the sum is 52.

The spelling of 16616622116581 in words is "sixteen trillion, six hundred sixteen billion, six hundred twenty-two million, one hundred sixteen thousand, five hundred eighty-one".