188443961989 has 2 divisors, whose sum is σ = 188443961990. Its totient is φ = 188443961988.

The previous prime is 188443961891. The next prime is 188443961999. The reversal of 188443961989 is 989169344881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151191101889 + 37252860100 = 388833^2 + 193010^2 .

It is a cyclic number.

It is not a de Polignac number, because 188443961989 - 2²¹ = 188441864837 is a prime.

It is a super-2 number, since 2×188443961989² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (188443961999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94221980994 + 94221980995.

It is an arithmetic number, because the mean of its divisors is an integer number (94221980995).

Almost surely, 2^188443961989 is an apocalyptic number.

It is an amenable number.

188443961989 is a deficient number, since it is larger than the sum of its proper divisors (1).

188443961989 is an equidigital number, since it uses as much as digits as its factorization.

188443961989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 107495424, while the sum is 70.

The spelling of 188443961989 in words is "one hundred eighty-eight billion, four hundred forty-three million, nine hundred sixty-one thousand, nine hundred eighty-nine".