211406221 has 4 divisors (see below), whose sum is σ = 227668252. Its totient is φ = 195144192.

The previous prime is 211406219. The next prime is 211406233. The reversal of 211406221 is 122604112.

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 120890025 + 90516196 = 10995^2 + 9514^2 .

It is a cyclic number.

It is not a de Polignac number, because 211406221 - 2¹ = 211406219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211406021) 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, 8130996 + ... + 8131021.

It is an arithmetic number, because the mean of its divisors is an integer number (56917063).

Almost surely, 2^211406221 is an apocalyptic number.

It is an amenable number.

211406221 is a deficient number, since it is larger than the sum of its proper divisors (16262031).

211406221 is a wasteful number, since it uses less digits than its factorization.

211406221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16262030.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 211406221 is about 14539.8150263337. The cubic root of 211406221 is about 595.7159857622.

The spelling of 211406221 in words is "two hundred eleven million, four hundred six thousand, two hundred twenty-one".