18777961721543 has 2 divisors, whose sum is σ = 18777961721544. Its totient is φ = 18777961721542.

The previous prime is 18777961721537. The next prime is 18777961721587. The reversal of 18777961721543 is 34512716977781.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18777961721543 - 2¹⁰ = 18777961720519 is a prime.

It is a super-2 number, since 2×18777961721543² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18777961727543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9388980860771 + 9388980860772.

It is an arithmetic number, because the mean of its divisors is an integer number (9388980860772).

Almost surely, 2^{18777961721543} is an apocalyptic number.

18777961721543 is a deficient number, since it is larger than the sum of its proper divisors (1).

18777961721543 is an equidigital number, since it uses as much as digits as its factorization.

18777961721543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124467840, while the sum is 68.

The spelling of 18777961721543 in words is "eighteen trillion, seven hundred seventy-seven billion, nine hundred sixty-one million, seven hundred twenty-one thousand, five hundred forty-three".