189881 has 2 divisors, whose sum is σ = 189882. Its totient is φ = 189880.

The previous prime is 189877. The next prime is 189887. The reversal of 189881 is 188981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 156025 + 33856 = 395^2 + 184^2 .

It is a cyclic number.

It is not a de Polignac number, because 189881 - 2² = 189877 is a prime.

It is a super-2 number, since 2×189881² = 72109588322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (189887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94940 + 94941.

It is an arithmetic number, because the mean of its divisors is an integer number (94941).

2¹⁸⁹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

189881 is a deficient number, since it is larger than the sum of its proper divisors (1).

189881 is an equidigital number, since it uses as much as digits as its factorization.

189881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 35.

The square root of 189881 is about 435.7533706123. The cubic root of 189881 is about 57.4769661995.

Subtracting from 189881 its reverse (188981), we obtain a square (900 = 30²).

The spelling of 189881 in words is "one hundred eighty-nine thousand, eight hundred eighty-one".