105981 has 4 divisors (see below), whose sum is σ = 141312. Its totient is φ = 70652.

The previous prime is 105977. The next prime is 105983. The reversal of 105981 is 189501.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 105981 - 2² = 105977 is a prime.

It is a super-2 number, since 2×105981² = 22463944722, which contains 22 as substring.

It is a D-number.

105981 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 105981.

It is not an unprimeable number, because it can be changed into a prime (105983) 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, 17661 + ... + 17666.

It is an arithmetic number, because the mean of its divisors is an integer number (35328).

2¹⁰⁵⁹⁸¹ is an apocalyptic number.

It is an amenable number.

105981 is a deficient number, since it is larger than the sum of its proper divisors (35331).

105981 is an equidigital number, since it uses as much as digits as its factorization.

105981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35330.

The product of its (nonzero) digits is 360, while the sum is 24.

The square root of 105981 is about 325.5472315963. The cubic root of 105981 is about 47.3234070745.

The spelling of 105981 in words is "one hundred five thousand, nine hundred eighty-one".