87121 has 2 divisors, whose sum is σ = 87122. Its totient is φ = 87120.

The previous prime is 87119. The next prime is 87133. The reversal of 87121 is 12178.

87121 is nontrivially palindromic in base 16.

It is the 121-st star number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 83521 + 3600 = 289^2 + 60^2 .

It is a cyclic number.

It is not a de Polignac number, because 87121 - 2¹ = 87119 is a prime.

Together with 87119, it forms a pair of twin primes.

87121 is a lucky number.

It is equal to p₈₄₆₁ and since 87121 and 8461 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (87151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43560 + 43561.

It is an arithmetic number, because the mean of its divisors is an integer number (43561).

2⁸⁷¹²¹ is an apocalyptic number.

It is an amenable number.

87121 is a deficient number, since it is larger than the sum of its proper divisors (1).

87121 is an equidigital number, since it uses as much as digits as its factorization.

87121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 112, while the sum is 19.

The square root of 87121 is about 295.1626670160. The cubic root of 87121 is about 44.3310091055.

Adding to 87121 its reverse (12178), we get a palindrome (99299).

The spelling of 87121 in words is "eighty-seven thousand, one hundred twenty-one".