193981 has 4 divisors (see below), whose sum is σ = 200700. Its totient is φ = 187264.

The previous prime is 193979. The next prime is 193993. The reversal of 193981 is 189391.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 133956 + 60025 = 366^2 + 245^2 .

It is a cyclic number.

It is not a de Polignac number, because 193981 - 2¹ = 193979 is a prime.

It is a super-2 number, since 2×193981² = 75257256722, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (193951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3316 + ... + 3373.

It is an arithmetic number, because the mean of its divisors is an integer number (50175).

2¹⁹³⁹⁸¹ is an apocalyptic number.

It is an amenable number.

193981 is a deficient number, since it is larger than the sum of its proper divisors (6719).

193981 is an equidigital number, since it uses as much as digits as its factorization.

193981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6718.

The product of its digits is 1944, while the sum is 31.

The square root of 193981 is about 440.4327417438. The cubic root of 193981 is about 57.8877137921.

The spelling of 193981 in words is "one hundred ninety-three thousand, nine hundred eighty-one".