189981 has 24 divisors (see below), whose sum is σ = 318240.
Its totient is φ = 108000.
The previous prime is 189977. The next prime is 189983.
It can be divided in two parts, 18 and 9981, that added together give a palindrome (9999).
189981 is nontrivially palindromic in base 10.
It is not a de Polignac number, because 189981 - 22 = 189977 is a prime.
It is a super-2 number, since 2×1899812 = 72185560722, which contains 22 as substring.
It is a Curzon number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (189983) by changing a digit.
It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1831 + ... + 1931.
It is an arithmetic number, because the mean of its divisors is an integer number (13260).
2189981 is an apocalyptic number.
189981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.
It is an amenable number.
189981 is a deficient number, since it is larger than the sum of its proper divisors (128259).
189981 is a wasteful number, since it uses less digits than its factorization.
189981 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 137 (or 134 counting only the distinct ones).
The product of its digits is 5184, while the sum is 36.
The square root of 189981 is about 435.8680993145.
The cubic root of 189981 is about 57.4870544265.
The spelling of 189981 in words is "one hundred eighty-nine thousand, nine hundred eighty-one".