2121021 has 24 divisors (see below), whose sum is σ = 3541824.
Its totient is φ = 1198080.
The previous prime is 2121017. The next prime is 2121023. The reversal of 2121021 is 1201212.
Adding to 2121021 its reverse (1201212), we get a palindrome (3322233).
2121021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is not a de Polignac number, because 2121021 - 22 = 2121017 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a junction number, because it is equal to n+sod(n) for n = 2120994 and 2121012.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (2121023) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8125 + ... + 8381.
It is an arithmetic number, because the mean of its divisors is an integer number (147576).
22121021 is an apocalyptic number.
2121021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.
It is an amenable number.
2121021 is a deficient number, since it is larger than the sum of its proper divisors (1420803).
2121021 is a wasteful number, since it uses less digits than its factorization.
2121021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 401 (or 398 counting only the distinct ones).
The product of its (nonzero) digits is 8, while the sum is 9.
The square root of 2121021 is about 1456.3725484916.
The cubic root of 2121021 is about 128.4837852433.
The spelling of 2121021 in words is "two million, one hundred twenty-one thousand, twenty-one".