189918910889 has 2 divisors, whose sum is σ = 189918910890. Its totient is φ = 189918910888.

The previous prime is 189918910871. The next prime is 189918910921. The reversal of 189918910889 is 988019819981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126659115664 + 63259795225 = 355892^2 + 251515^2 .

It is an emirp because it is prime and its reverse (988019819981) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-189918910889 is a prime.

It is not a weakly prime, because it can be changed into another prime (189918910789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94959455444 + 94959455445.

It is an arithmetic number, because the mean of its divisors is an integer number (94959455445).

Almost surely, 2^189918910889 is an apocalyptic number.

It is an amenable number.

189918910889 is a deficient number, since it is larger than the sum of its proper divisors (1).

189918910889 is an equidigital number, since it uses as much as digits as its factorization.

189918910889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26873856, while the sum is 71.

The spelling of 189918910889 in words is "one hundred eighty-nine billion, nine hundred eighteen million, nine hundred ten thousand, eight hundred eighty-nine".