211210221 has 16 divisors (see below), whose sum is σ = 284828544. Its totient is φ = 139206144.

The previous prime is 211210217. The next prime is 211210249. The reversal of 211210221 is 122012112.

It is not a de Polignac number, because 211210221 - 2² = 211210217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 211210197 and 211210206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211210921) 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, 246025 + ... + 246881.

It is an arithmetic number, because the mean of its divisors is an integer number (17801784).

Almost surely, 2^211210221 is an apocalyptic number.

It is an amenable number.

211210221 is a deficient number, since it is larger than the sum of its proper divisors (73618323).

211210221 is a wasteful number, since it uses less digits than its factorization.

211210221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1700.

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

The square root of 211210221 is about 14533.0733501211. The cubic root of 211210221 is about 595.5318277700.

Adding to 211210221 its reverse (122012112), we get a palindrome (333222333).

The spelling of 211210221 in words is "two hundred eleven million, two hundred ten thousand, two hundred twenty-one".