105781 has 8 divisors (see below), whose sum is σ = 116480. Its totient is φ = 95472.

The previous prime is 105769. The next prime is 105817. The reversal of 105781 is 187501.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 105781 - 2⁷ = 105653 is a prime.

It is a super-2 number, since 2×105781² = 22379239922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (105701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 976 + ... + 1078.

It is an arithmetic number, because the mean of its divisors is an integer number (14560).

2¹⁰⁵⁷⁸¹ is an apocalyptic number.

105781 is the 206-th heptagonal number.

It is an amenable number.

105781 is a deficient number, since it is larger than the sum of its proper divisors (10699).

105781 is a wasteful number, since it uses less digits than its factorization.

105781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195.

The product of its (nonzero) digits is 280, while the sum is 22.

The square root of 105781 is about 325.2399114500. The cubic root of 105781 is about 47.2936198442.

Subtracting from 105781 its product of nonzero digits (280), we obtain a palindrome (105501).

The spelling of 105781 in words is "one hundred five thousand, seven hundred eighty-one".