121521543 has 16 divisors (see below), whose sum is σ = 190356096. Its totient is φ = 67983840.

The previous prime is 121521529. The next prime is 121521583. The reversal of 121521543 is 345125121.

It is a happy number.

It is not a de Polignac number, because 121521543 - 2¹⁰ = 121520519 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121521523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 141205 + ... + 142062.

It is an arithmetic number, because the mean of its divisors is an integer number (11897256).

Almost surely, 2^121521543 is an apocalyptic number.

121521543 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

121521543 is a deficient number, since it is larger than the sum of its proper divisors (68834553).

121521543 is a wasteful number, since it uses less digits than its factorization.

121521543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283294.

The product of its digits is 1200, while the sum is 24.

The square root of 121521543 is about 11023.6810095358. The cubic root of 121521543 is about 495.3183586161.

Adding to 121521543 its reverse (345125121), we get a palindrome (466646664).

It can be divided in two parts, 12152 and 1543, that added together give a triangular number (13695 = T₁₆₅).

The spelling of 121521543 in words is "one hundred twenty-one million, five hundred twenty-one thousand, five hundred forty-three".