2021111221 has 4 divisors (see below), whose sum is σ = 2022192172. Its totient is φ = 2020030272.

The previous prime is 2021111207. The next prime is 2021111243. The reversal of 2021111221 is 1221111202.

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 215796100 + 1805315121 = 14690^2 + 42489^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021111221 - 2⁵ = 2021111189 is a prime.

It is a super-2 number, since 2×2021111221² = 8169781135304221682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021111251) 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, 537666 + ... + 541411.

It is an arithmetic number, because the mean of its divisors is an integer number (505548043).

Almost surely, 2^2021111221 is an apocalyptic number.

It is an amenable number.

2021111221 is a deficient number, since it is larger than the sum of its proper divisors (1080951).

2021111221 is a wasteful number, since it uses less digits than its factorization.

2021111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1080950.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 2021111221 is about 44956.7705801918. The cubic root of 2021111221 is about 1264.3386213968.

Adding to 2021111221 its reverse (1221111202), we get a palindrome (3242222423).

The spelling of 2021111221 in words is "two billion, twenty-one million, one hundred eleven thousand, two hundred twenty-one".