4021209 has 12 divisors (see below), whose sum is σ = 5832996. Its totient is φ = 2669472.

The previous prime is 4021207. The next prime is 4021211. The reversal of 4021209 is 9021204.

It is an interprime number because it is at equal distance from previous prime (4021207) and next prime (4021211).

It can be written as a sum of positive squares in 2 ways, for example, as 1550025 + 2471184 = 1245^2 + 1572^2 .

It is not a de Polignac number, because 4021209 - 2¹ = 4021207 is a prime.

4021209 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 4021191 and 4021200.

It is not an unprimeable number, because it can be changed into a prime (4021207) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1687 + ... + 3299.

It is an arithmetic number, because the mean of its divisors is an integer number (486083).

Almost surely, 2^4021209 is an apocalyptic number.

It is an amenable number.

4021209 is a deficient number, since it is larger than the sum of its proper divisors (1811787).

4021209 is a wasteful number, since it uses less digits than its factorization.

4021209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1896 (or 1893 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 4021209 is about 2005.2952401080. The cubic root of 4021209 is about 159.0201706937.

The spelling of 4021209 in words is "four million, twenty-one thousand, two hundred nine".