11978932181 has 2 divisors, whose sum is σ = 11978932182. Its totient is φ = 11978932180.

The previous prime is 11978932171. The next prime is 11978932193. The reversal of 11978932181 is 18123987911.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11123077156 + 855855025 = 105466^2 + 29255^2 .

It is a cyclic number.

It is not a de Polignac number, because 11978932181 - 2⁶ = 11978932117 is a prime.

It is a super-2 number, since 2×11978932181² (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 (11978932171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5989466090 + 5989466091.

It is an arithmetic number, because the mean of its divisors is an integer number (5989466091).

Almost surely, 2^11978932181 is an apocalyptic number.

It is an amenable number.

11978932181 is a deficient number, since it is larger than the sum of its proper divisors (1).

11978932181 is an equidigital number, since it uses as much as digits as its factorization.

11978932181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 50.

The spelling of 11978932181 in words is "eleven billion, nine hundred seventy-eight million, nine hundred thirty-two thousand, one hundred eighty-one".