18780562781 has 2 divisors, whose sum is σ = 18780562782. Its totient is φ = 18780562780.

The previous prime is 18780562763. The next prime is 18780562789. The reversal of 18780562781 is 18726508781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18351037156 + 429525625 = 135466^2 + 20725^2 .

It is an emirp because it is prime and its reverse (18726508781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18780562781 - 2¹⁰ = 18780561757 is a prime.

It is a super-2 number, since 2×18780562781² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18780562789) 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, 9390281390 + 9390281391.

It is an arithmetic number, because the mean of its divisors is an integer number (9390281391).

Almost surely, 2^18780562781 is an apocalyptic number.

It is an amenable number.

18780562781 is a deficient number, since it is larger than the sum of its proper divisors (1).

18780562781 is an equidigital number, since it uses as much as digits as its factorization.

18780562781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1505280, while the sum is 53.

The spelling of 18780562781 in words is "eighteen billion, seven hundred eighty million, five hundred sixty-two thousand, seven hundred eighty-one".