221021211 has 16 divisors (see below), whose sum is σ = 298438400. Its totient is φ = 145484640.

The previous prime is 221021197. The next prime is 221021221. The reversal of 221021211 is 112120122.

It is not a de Polignac number, because 221021211 - 2⁵ = 221021179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221021221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 129240 + ... + 130938.

It is an arithmetic number, because the mean of its divisors is an integer number (18652400).

Almost surely, 2^221021211 is an apocalyptic number.

221021211 is a deficient number, since it is larger than the sum of its proper divisors (77417189).

221021211 is a wasteful number, since it uses less digits than its factorization.

221021211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2226.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 221021211 is about 14866.7821333334. The cubic root of 221021211 is about 604.6137014424.

Adding to 221021211 its reverse (112120122), we get a palindrome (333141333).

The spelling of 221021211 in words is "two hundred twenty-one million, twenty-one thousand, two hundred eleven".