18200180861 has 2 divisors, whose sum is σ = 18200180862. Its totient is φ = 18200180860.

The previous prime is 18200180857. The next prime is 18200180917. The reversal of 18200180861 is 16808100281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17389696900 + 810483961 = 131870^2 + 28469^2 .

It is a cyclic number.

It is not a de Polignac number, because 18200180861 - 2² = 18200180857 is a prime.

It is a super-2 number, since 2×18200180861² (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 (18200180851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9100090430 + 9100090431.

It is an arithmetic number, because the mean of its divisors is an integer number (9100090431).

Almost surely, 2^18200180861 is an apocalyptic number.

It is an amenable number.

18200180861 is a deficient number, since it is larger than the sum of its proper divisors (1).

18200180861 is an equidigital number, since it uses as much as digits as its factorization.

18200180861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6144, while the sum is 35.

The spelling of 18200180861 in words is "eighteen billion, two hundred million, one hundred eighty thousand, eight hundred sixty-one".