2121121 has 2 divisors, whose sum is σ = 2121122.
Its totient is φ = 2121120.
The previous prime is 2121043. The next prime is 2121127. The reversal of 2121121 is 1211212.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 2117025 + 4096 = 1455^2 + 64^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-2121121 is a prime.
2121121 is a lucky number.
It is a junction number, because it is equal to n+sod(n) for n = 2121098 and 2121107.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (2121127) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060560 + 1060561.
It is an arithmetic number, because the mean of its divisors is an integer number (1060561).
22121121 is an apocalyptic number.
It is an amenable number.
2121121 is a deficient number, since it is larger than the sum of its proper divisors (1).
2121121 is an equidigital number, since it uses as much as digits as its factorization.
2121121 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 8, while the sum is 10.
The square root of 2121121 is about 1456.4068799618.
The cubic root of 2121121 is about 128.4858044244.
Adding to 2121121 its reverse (1211212), we get a palindrome (3332333).
Subtracting from 2121121 its reverse (1211212), we obtain a palindrome (909909).
It can be divided in two parts, 2 and 121121, that multiplied together give a palindrome (242242).
The spelling of 2121121 in words is "two million, one hundred twenty-one thousand, one hundred twenty-one".