18361967557 has 2 divisors, whose sum is σ = 18361967558. Its totient is φ = 18361967556.

The previous prime is 18361967513. The next prime is 18361967581. The reversal of 18361967557 is 75576916381.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18300407841 + 61559716 = 135279^2 + 7846^2 .

It is a cyclic number.

It is not a de Polignac number, because 18361967557 - 2²⁷ = 18227749829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18361961557) 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, 9180983778 + 9180983779.

It is an arithmetic number, because the mean of its divisors is an integer number (9180983779).

Almost surely, 2^18361967557 is an apocalyptic number.

It is an amenable number.

18361967557 is a deficient number, since it is larger than the sum of its proper divisors (1).

18361967557 is an equidigital number, since it uses as much as digits as its factorization.

18361967557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9525600, while the sum is 58.

The spelling of 18361967557 in words is "eighteen billion, three hundred sixty-one million, nine hundred sixty-seven thousand, five hundred fifty-seven".