18565216949 has 2 divisors, whose sum is σ = 18565216950. Its totient is φ = 18565216948.

The previous prime is 18565216913. The next prime is 18565216961. The reversal of 18565216949 is 94961256581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17064196900 + 1501020049 = 130630^2 + 38743^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18565216949 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 18565216894 and 18565216903.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18565216909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9282608474 + 9282608475.

It is an arithmetic number, because the mean of its divisors is an integer number (9282608475).

Almost surely, 2^18565216949 is an apocalyptic number.

It is an amenable number.

18565216949 is a deficient number, since it is larger than the sum of its proper divisors (1).

18565216949 is an equidigital number, since it uses as much as digits as its factorization.

18565216949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4665600, while the sum is 56.

The spelling of 18565216949 in words is "eighteen billion, five hundred sixty-five million, two hundred sixteen thousand, nine hundred forty-nine".