82121 has 4 divisors (see below), whose sum is σ = 88452. Its totient is φ = 75792.

The previous prime is 82073. The next prime is 82129. The reversal of 82121 is 12128.

Added to its reverse (12128) it gives a square (94249 = 307²).

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26896 + 55225 = 164^2 + 235^2 .

It is a cyclic number.

It is not a de Polignac number, because 82121 - 2¹⁰ = 81097 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 82096 and 82105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82129) 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, 3146 + ... + 3171.

It is an arithmetic number, because the mean of its divisors is an integer number (22113).

2⁸²¹²¹ is an apocalyptic number.

It is an amenable number.

82121 is a deficient number, since it is larger than the sum of its proper divisors (6331).

82121 is a wasteful number, since it uses less digits than its factorization.

82121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6330.

The product of its digits is 32, while the sum is 14.

The square root of 82121 is about 286.5676185475. The cubic root of 82121 is about 43.4661735530.

Adding to 82121 its reverse (12128), we get a palindrome (94249).

The spelling of 82121 in words is "eighty-two thousand, one hundred twenty-one".