2021221 has 4 divisors (see below), whose sum is σ = 2026444. Its totient is φ = 2016000.

The previous prime is 2021219. The next prime is 2021237. The reversal of 2021221 is 1221202.

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 408321 + 1612900 = 639^2 + 1270^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021221 - 2¹ = 2021219 is a prime.

It is a Duffinian number.

2021221 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 2021198 and 2021207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1980 + ... + 2821.

It is an arithmetic number, because the mean of its divisors is an integer number (506611).

2^2021221 is an apocalyptic number.

It is an amenable number.

2021221 is a deficient number, since it is larger than the sum of its proper divisors (5223).

2021221 is an equidigital number, since it uses as much as digits as its factorization.

2021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5222.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 2021221 is about 1421.6965217655. The cubic root of 2021221 is about 126.4361512322.

Adding to 2021221 its reverse (1221202), we get a palindrome (3242423).

It can be divided in two parts, 202 and 1221, that multiplied together give a palindrome (246642).

The spelling of 2021221 in words is "two million, twenty-one thousand, two hundred twenty-one".