211212222220121 has 4 divisors (see below), whose sum is σ = 220395362316672. Its totient is φ = 202029082123572.

The previous prime is 211212222220073. The next prime is 211212222220183. The reversal of 211212222220121 is 121022222212112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 211212222220121 - 2¹⁸ = 211212221957977 is a prime.

It is a super-2 number, since 2×211212222220121² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 9183140096527 = 211212222220121 / (2 + 1 + 1 + 2 + 1 + 2 + 2 + 2 + 2 + 2 + 2 + 0 + 1 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211212222220421) 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, 4591570048241 + ... + 4591570048286.

It is an arithmetic number, because the mean of its divisors is an integer number (55098840579168).

Almost surely, 2^{211212222220121} is an apocalyptic number.

It is an amenable number.

211212222220121 is a deficient number, since it is larger than the sum of its proper divisors (9183140096551).

211212222220121 is an equidigital number, since it uses as much as digits as its factorization.

211212222220121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9183140096550.

The product of its (nonzero) digits is 512, while the sum is 23.

Adding to 211212222220121 its reverse (121022222212112), we get a palindrome (332234444432233).

The spelling of 211212222220121 in words is "two hundred eleven trillion, two hundred twelve billion, two hundred twenty-two million, two hundred twenty thousand, one hundred twenty-one".