211221121 has 8 divisors (see below), whose sum is σ = 224141760. Its totient is φ = 198611952.

The previous prime is 211221091. The next prime is 211221169. The reversal of 211221121 is 121122112.

211221121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 211221121 - 2⁷ = 211220993 is a prime.

It is a super-2 number, since 2×211221121² = 89228723912993282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211221421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76470 + ... + 79183.

It is an arithmetic number, because the mean of its divisors is an integer number (28017720).

Almost surely, 2^211221121 is an apocalyptic number.

It is an amenable number.

211221121 is a deficient number, since it is larger than the sum of its proper divisors (12920639).

211221121 is a wasteful number, since it uses less digits than its factorization.

211221121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155735.

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

The square root of 211221121 is about 14533.4483519913. The cubic root of 211221121 is about 595.5420722004.

Adding to 211221121 its reverse (121122112), we get a palindrome (332343233).

Subtracting from 211221121 its reverse (121122112), we obtain a palindrome (90099009).

It can be divided in two parts, 21 and 1221121, that multiplied together give a triangular number (25643541 = T₇₁₆₁).

The spelling of 211221121 in words is "two hundred eleven million, two hundred twenty-one thousand, one hundred twenty-one".