16505210989 has 2 divisors, whose sum is σ = 16505210990. Its totient is φ = 16505210988.

The previous prime is 16505210963. The next prime is 16505210993. The reversal of 16505210989 is 98901250561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15359388489 + 1145822500 = 123933^2 + 33850^2 .

It is an emirp because it is prime and its reverse (98901250561) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16505210989 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16505210489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8252605494 + 8252605495.

It is an arithmetic number, because the mean of its divisors is an integer number (8252605495).

Almost surely, 2^16505210989 is an apocalyptic number.

It is an amenable number.

16505210989 is a deficient number, since it is larger than the sum of its proper divisors (1).

16505210989 is an equidigital number, since it uses as much as digits as its factorization.

16505210989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 194400, while the sum is 46.

The spelling of 16505210989 in words is "sixteen billion, five hundred five million, two hundred ten thousand, nine hundred eighty-nine".