4181 has 4 divisors (see below), whose sum is σ = 4332. Its totient is φ = 4032.
The previous prime is 4177. The next prime is 4201. The reversal of 4181 is 1814.
Added to its reverse (1814) it gives a triangular number (5995 = T109).
It is a happy number.
It is the 19-th Fibonacci number F19.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1814 = 2 ⋅907.
It can be written as a sum of positive squares in 2 ways, for example, as 1681 + 2500 = 41^2 + 50^2 .
It is a cyclic number.
It is not a de Polignac number, because 4181 - 22 = 4177 is a prime.
It is a super-2 number, since 2×41812 = 34961522, which contains 22 as substring.
It is an alternating number because its digits alternate between even and odd.
It is a Duffinian number.
It is a Curzon number.
It is a plaindrome in base 15.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (4111) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (5) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20 + ... + 93.
It is an arithmetic number, because the mean of its divisors is an integer number (1083).
24181 is an apocalyptic number.
It is an amenable number.
4181 is a deficient number, since it is larger than the sum of its proper divisors (151).
4181 is a wasteful number, since it uses less digits than its factorization.
4181 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 150.
The product of its digits is 32, while the sum is 14.
The square root of 4181 is about 64.6606526413. The cubic root of 4181 is about 16.1099202009.
Adding to 4181 its reverse (1814), we get a palindrome (5995).
It can be divided in two parts, 41 and 81, that multiplied together give a triangular number (3321 = T81).
The spelling of 4181 in words is "four thousand, one hundred eighty-one".
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