2122121 has 4 divisors (see below), whose sum is σ = 2141700. Its totient is φ = 2102544.

The previous prime is 2122103. The next prime is 2122123. The reversal of 2122121 is 1212212.

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 1132096 + 990025 = 1064^2 + 995^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2122121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2122123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9626 + ... + 9843.

It is an arithmetic number, because the mean of its divisors is an integer number (535425).

2^2122121 is an apocalyptic number.

It is an amenable number.

2122121 is a deficient number, since it is larger than the sum of its proper divisors (19579).

2122121 is a wasteful number, since it uses less digits than its factorization.

2122121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19578.

The product of its digits is 16, while the sum is 11.

The square root of 2122121 is about 1456.7501501630. The cubic root of 2122121 is about 128.5059927459.

Adding to 2122121 its reverse (1212212), we get a palindrome (3334333).

Subtracting from 2122121 its reverse (1212212), we obtain a palindrome (909909).

The spelling of 2122121 in words is "two million, one hundred twenty-two thousand, one hundred twenty-one".