2121409 has 4 divisors (see below), whose sum is σ = 2151360. Its totient is φ = 2091460.

The previous prime is 2121403. The next prime is 2121433. The reversal of 2121409 is 9041212.

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.

It is a cyclic number.

It is not a de Polignac number, because 2121409 - 2⁵ = 2121377 is a prime.

It is a super-2 number, since 2×2121409² = 9000752290562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121403) 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, 14869 + ... + 15010.

It is an arithmetic number, because the mean of its divisors is an integer number (537840).

2^2121409 is an apocalyptic number.

It is an amenable number.

2121409 is a deficient number, since it is larger than the sum of its proper divisors (29951).

2121409 is an equidigital number, since it uses as much as digits as its factorization.

2121409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29950.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 2121409 is about 1456.5057500745. The cubic root of 2121409 is about 128.4916193114.

The spelling of 2121409 in words is "two million, one hundred twenty-one thousand, four hundred nine".