121543 has 4 divisors (see below), whose sum is σ = 127960. Its totient is φ = 115128.

The previous prime is 121531. The next prime is 121547. The reversal of 121543 is 345121.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121543 is a prime.

It is a Duffinian number.

121543 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3180 + ... + 3217.

It is an arithmetic number, because the mean of its divisors is an integer number (31990).

2¹²¹⁵⁴³ is an apocalyptic number.

121543 is a deficient number, since it is larger than the sum of its proper divisors (6417).

121543 is an equidigital number, since it uses as much as digits as its factorization.

121543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6416.

The product of its digits is 120, while the sum is 16.

The square root of 121543 is about 348.6301765482. The cubic root of 121543 is about 49.5347509608.

Adding to 121543 its reverse (345121), we get a palindrome (466664).

It can be divided in two parts, 121 and 543, that multiplied together give a triangular number (65703 = T₃₆₂).

The spelling of 121543 in words is "one hundred twenty-one thousand, five hundred forty-three".