103781 has 4 divisors (see below), whose sum is σ = 105600. Its totient is φ = 101964.

The previous prime is 103769. The next prime is 103787. The reversal of 103781 is 187301.

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, and also an emirpimes, since its reverse is a distinct semiprime: 187301 = 157 ⋅1193.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-103781 is a prime.

It is a super-2 number, since 2×103781² = 21540991922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (103787) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 821 + ... + 938.

It is an arithmetic number, because the mean of its divisors is an integer number (26400).

2¹⁰³⁷⁸¹ is an apocalyptic number.

It is an amenable number.

103781 is a deficient number, since it is larger than the sum of its proper divisors (1819).

103781 is an equidigital number, since it uses as much as digits as its factorization.

103781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1818.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 103781 is about 322.1505859067. The cubic root of 103781 is about 46.9936614358.

The spelling of 103781 in words is "one hundred three thousand, seven hundred eighty-one".