8121 has 4 divisors (see below), whose sum is σ = 10832. Its totient is φ = 5412.

The previous prime is 8117. The next prime is 8123. The reversal of 8121 is 1218.

It is a happy number.

8121 is nontrivially palindromic in base 8.

8121 is an esthetic number in base 9, because in such base its adjacent digits differ by 1.

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 not a de Polignac number, because 8121 - 2² = 8117 is a prime.

It is a D-number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 8097 and 8106.

It is not an unprimeable number, because it can be changed into a prime (8123) 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, 1351 + ... + 1356.

It is an arithmetic number, because the mean of its divisors is an integer number (2708).

2⁸¹²¹ is an apocalyptic number.

It is an amenable number.

8121 is a deficient number, since it is larger than the sum of its proper divisors (2711).

8121 is a wasteful number, since it uses less digits than its factorization.

8121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2710.

The product of its digits is 16, while the sum is 12.

The square root of 8121 is about 90.1165911472. The cubic root of 8121 is about 20.1003291944.

Adding to 8121 its reverse (1218), we get a palindrome (9339).

Subtracting from 8121 its reverse (1218), we obtain a triangular number (6903 = T₁₁₇).

The spelling of 8121 in words is "eight thousand, one hundred twenty-one".