1811680861181 has 2 divisors, whose sum is σ = 1811680861182. Its totient is φ = 1811680861180.

The previous prime is 1811680861171. The next prime is 1811680861229.

1811680861181 is nontrivially palindromic in base 10.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1667884429156 + 143796432025 = 1291466^2 + 379205^2 .

It is a palprime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1811680861181 is a prime.

It is a super-2 number, since 2×1811680861181² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1811680861171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 905840430590 + 905840430591.

It is an arithmetic number, because the mean of its divisors is an integer number (905840430591).

Almost surely, 2^{1811680861181} is an apocalyptic number.

It is an amenable number.

1811680861181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1811680861181 is an equidigital number, since it uses as much as digits as its factorization.

1811680861181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 147456, while the sum is 50.

The spelling of 1811680861181 in words is "one trillion, eight hundred eleven billion, six hundred eighty million, eight hundred sixty-one thousand, one hundred eighty-one".