213121111 has 8 divisors (see below), whose sum is σ = 245932544. Its totient is φ = 180901080.

The previous prime is 213121093. The next prime is 213121123. The reversal of 213121111 is 111121312.

It is a happy number.

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 213121111 - 2⁵ = 213121079 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213121091 and 213121100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213121141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 147075 + ... + 148516.

It is an arithmetic number, because the mean of its divisors is an integer number (30741568).

Almost surely, 2^213121111 is an apocalyptic number.

213121111 is a deficient number, since it is larger than the sum of its proper divisors (32811433).

213121111 is a wasteful number, since it uses less digits than its factorization.

213121111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295701.

The product of its digits is 12, while the sum is 13.

The square root of 213121111 is about 14598.6681241817. The cubic root of 213121111 is about 597.3224308507.

Adding to 213121111 its reverse (111121312), we get a palindrome (324242423).

It can be divided in two parts, 21312 and 1111, that multiplied together give a palindrome (23677632).

The spelling of 213121111 in words is "two hundred thirteen million, one hundred twenty-one thousand, one hundred eleven".