18945561577 has 2 divisors, whose sum is σ = 18945561578. Its totient is φ = 18945561576.

The previous prime is 18945561539. The next prime is 18945561623. The reversal of 18945561577 is 77516554981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16650289296 + 2295272281 = 129036^2 + 47909^2 .

It is a cyclic number.

It is not a de Polignac number, because 18945561577 - 2¹⁹ = 18945037289 is a prime.

It is not a weakly prime, because it can be changed into another prime (18945561077) 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, 9472780788 + 9472780789.

It is an arithmetic number, because the mean of its divisors is an integer number (9472780789).

Almost surely, 2^18945561577 is an apocalyptic number.

It is an amenable number.

18945561577 is a deficient number, since it is larger than the sum of its proper divisors (1).

18945561577 is an equidigital number, since it uses as much as digits as its factorization.

18945561577 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10584000, while the sum is 58.

The spelling of 18945561577 in words is "eighteen billion, nine hundred forty-five million, five hundred sixty-one thousand, five hundred seventy-seven".