2021220221 has 4 divisors (see below), whose sum is σ = 2090917500. Its totient is φ = 1951522944.

The previous prime is 2021220211. The next prime is 2021220239. The reversal of 2021220221 is 1220221202.

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 1373517721 + 647702500 = 37061^2 + 25450^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2021220221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2021220196 and 2021220205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021220211) 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, 34848596 + ... + 34848653.

It is an arithmetic number, because the mean of its divisors is an integer number (522729375).

Almost surely, 2^2021220221 is an apocalyptic number.

It is an amenable number.

2021220221 is a deficient number, since it is larger than the sum of its proper divisors (69697279).

2021220221 is an equidigital number, since it uses as much as digits as its factorization.

2021220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69697278.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 2021220221 is about 44957.9828395359. The cubic root of 2021220221 is about 1264.3613498891.

Adding to 2021220221 its reverse (1220221202), we get a palindrome (3241441423).

It can be divided in two parts, 202 and 1220221, that multiplied together give a palindrome (246484642).

The spelling of 2021220221 in words is "two billion, twenty-one million, two hundred twenty thousand, two hundred twenty-one".