189918911081 has 2 divisors, whose sum is σ = 189918911082. Its totient is φ = 189918911080.

The previous prime is 189918911029. The next prime is 189918911123. The reversal of 189918911081 is 180119819981.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 187886704681 + 2032206400 = 433459^2 + 45080^2 .

It is a cyclic number.

It is not a de Polignac number, because 189918911081 - 2¹⁸ = 189918648937 is a prime.

It is a super-3 number, since 3×189918911081³ (a number of 35 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (189918941081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94959455540 + 94959455541.

It is an arithmetic number, because the mean of its divisors is an integer number (94959455541).

Almost surely, 2^189918911081 is an apocalyptic number.

It is an amenable number.

189918911081 is a deficient number, since it is larger than the sum of its proper divisors (1).

189918911081 is an equidigital number, since it uses as much as digits as its factorization.

189918911081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 56.

The spelling of 189918911081 in words is "one hundred eighty-nine billion, nine hundred eighteen million, nine hundred eleven thousand, eighty-one".