121203121 has 4 divisors (see below), whose sum is σ = 130526452. Its totient is φ = 111879792.

The previous prime is 121203119. The next prime is 121203127. The reversal of 121203121 is 121302121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121302121 = 3779 ⋅32099.

It can be written as a sum of positive squares in 2 ways, for example, as 65028096 + 56175025 = 8064^2 + 7495^2 .

It is a cyclic number.

It is not a de Polignac number, because 121203121 - 2¹ = 121203119 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 9323317 = 121203121 / (1 + 2 + 1 + 2 + 0 + 3 + 1 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121203127) 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, 4661646 + ... + 4661671.

It is an arithmetic number, because the mean of its divisors is an integer number (32631613).

Almost surely, 2^121203121 is an apocalyptic number.

It is an amenable number.

121203121 is a deficient number, since it is larger than the sum of its proper divisors (9323331).

121203121 is an equidigital number, since it uses as much as digits as its factorization.

121203121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9323330.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 121203121 is about 11009.2289012446. The cubic root of 121203121 is about 494.8853538524.

Adding to 121203121 its reverse (121302121), we get a palindrome (242505242).

The spelling of 121203121 in words is "one hundred twenty-one million, two hundred three thousand, one hundred twenty-one".