211321213121 has 4 divisors (see below), whose sum is σ = 211346691012. Its totient is φ = 211295735232.

The previous prime is 211321213091. The next prime is 211321213123. The reversal of 211321213121 is 121312123112.

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 151582520896 + 59738692225 = 389336^2 + 244415^2 .

It is a cyclic number.

It is not a de Polignac number, because 211321213121 - 2⁶ = 211321213057 is a prime.

It is a super-2 number, since 2×211321213121² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211321213093 and 211321213102.

It is not an unprimeable number, because it can be changed into a prime (211321213123) 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, 12726500 + ... + 12743093.

It is an arithmetic number, because the mean of its divisors is an integer number (52836672753).

Almost surely, 2^211321213121 is an apocalyptic number.

It is an amenable number.

211321213121 is a deficient number, since it is larger than the sum of its proper divisors (25477891).

211321213121 is an equidigital number, since it uses as much as digits as its factorization.

211321213121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25477890.

The product of its digits is 144, while the sum is 20.

Adding to 211321213121 its reverse (121312123112), we get a palindrome (332633336233).

Subtracting from 211321213121 its reverse (121312123112), we obtain a palindrome (90009090009).

The spelling of 211321213121 in words is "two hundred eleven billion, three hundred twenty-one million, two hundred thirteen thousand, one hundred twenty-one".