4121 has 4 divisors (see below), whose sum is σ = 4452. Its totient is φ = 3792.

The previous prime is 4111. The next prime is 4127. The reversal of 4121 is 1214.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1214 = 2 ⋅607.

It can be written as a sum of positive squares in 2 ways, for example, as 400 + 3721 = 20^2 + 61^2 .

It is a cyclic number.

It is not a de Polignac number, because 4121 - 2⁶ = 4057 is a prime.

It is an Ulam number.

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 9 and base 15.

It is a junction number, because it is equal to n+sod(n) for n = 4099 and 4108.

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 4121.

It is not an unprimeable number, because it can be changed into a prime (4127) 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, 146 + ... + 171.

It is an arithmetic number, because the mean of its divisors is an integer number (1113).

2⁴¹²¹ is an apocalyptic number.

It is an amenable number.

4121 is a deficient number, since it is larger than the sum of its proper divisors (331).

4121 is a wasteful number, since it uses less digits than its factorization.

4121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330.

The product of its digits is 8, while the sum is 8.

The square root of 4121 is about 64.1950153828. The cubic root of 4121 is about 16.0324860796.

Adding to 4121 its reverse (1214), we get a palindrome (5335).

It can be divided in two parts, 41 and 21, that multiplied together give a triangular number (861 = T₄₁).

The spelling of 4121 in words is "four thousand, one hundred twenty-one", and thus it is an iban number.