188443961891 has 2 divisors, whose sum is σ = 188443961892. Its totient is φ = 188443961890.

The previous prime is 188443961773. The next prime is 188443961989. The reversal of 188443961891 is 198169344881.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 188443961891 - 2¹⁰ = 188443960867 is a prime.

It is a super-2 number, since 2×188443961891² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (188443961191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94221980945 + 94221980946.

It is an arithmetic number, because the mean of its divisors is an integer number (94221980946).

Almost surely, 2^188443961891 is an apocalyptic number.

188443961891 is a deficient number, since it is larger than the sum of its proper divisors (1).

188443961891 is an equidigital number, since it uses as much as digits as its factorization.

188443961891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11943936, while the sum is 62.

The spelling of 188443961891 in words is "one hundred eighty-eight billion, four hundred forty-three million, nine hundred sixty-one thousand, eight hundred ninety-one".