18923686549 has 2 divisors, whose sum is σ = 18923686550. Its totient is φ = 18923686548.

The previous prime is 18923686543. The next prime is 18923686583. The reversal of 18923686549 is 94568632981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14329287025 + 4594399524 = 119705^2 + 67782^2 .

It is a cyclic number.

It is not a de Polignac number, because 18923686549 - 2¹¹ = 18923684501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18923686543) 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, 9461843274 + 9461843275.

It is an arithmetic number, because the mean of its divisors is an integer number (9461843275).

Almost surely, 2^18923686549 is an apocalyptic number.

It is an amenable number.

18923686549 is a deficient number, since it is larger than the sum of its proper divisors (1).

18923686549 is an equidigital number, since it uses as much as digits as its factorization.

18923686549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22394880, while the sum is 61.

The spelling of 18923686549 in words is "eighteen billion, nine hundred twenty-three million, six hundred eighty-six thousand, five hundred forty-nine".