121409 has 4 divisors (see below), whose sum is σ = 122304. Its totient is φ = 120516.

The previous prime is 121403. The next prime is 121421. The reversal of 121409 is 904121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121409 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (121403) 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, 197 + ... + 530.

It is an arithmetic number, because the mean of its divisors is an integer number (30576).

2¹²¹⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

121409 is a deficient number, since it is larger than the sum of its proper divisors (895).

121409 is an equidigital number, since it uses as much as digits as its factorization.

121409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 894.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 121409 is about 348.4379428248. The cubic root of 121409 is about 49.5165404031.

The spelling of 121409 in words is "one hundred twenty-one thousand, four hundred nine".