2121305 has 4 divisors (see below), whose sum is σ = 2545572. Its totient is φ = 1697040.

The previous prime is 2121289. The next prime is 2121323. The reversal of 2121305 is 5031212.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 712336 + 1408969 = 844^2 + 1187^2 .

It is not a de Polignac number, because 2121305 - 2⁴ = 2121289 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2121305.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212126 + ... + 212135.

It is an arithmetic number, because the mean of its divisors is an integer number (636393).

2^2121305 is an apocalyptic number.

It is an amenable number.

2121305 is a deficient number, since it is larger than the sum of its proper divisors (424267).

2121305 is an equidigital number, since it uses as much as digits as its factorization.

2121305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424266.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 2121305 is about 1456.4700477524. The cubic root of 2121305 is about 128.4895195518.

Adding to 2121305 its reverse (5031212), we get a palindrome (7152517).

The spelling of 2121305 in words is "two million, one hundred twenty-one thousand, three hundred five".