221212100011121 has 4 divisors (see below), whose sum is σ = 225385913218932. Its totient is φ = 217038286803312.

The previous prime is 221212100011109. The next prime is 221212100011211. The reversal of 221212100011121 is 121110001212122.

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 62990016390625 + 158222083620496 = 7936625^2 + 12578636^2 .

It is a cyclic number.

It is not a de Polignac number, because 221212100011121 - 2¹⁴ = 221212099994737 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221212100011121.

It is not an unprimeable number, because it can be changed into a prime (221212100911121) 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, 2086906603826 + ... + 2086906603931.

It is an arithmetic number, because the mean of its divisors is an integer number (56346478304733).

Almost surely, 2^{221212100011121} is an apocalyptic number.

It is an amenable number.

221212100011121 is a deficient number, since it is larger than the sum of its proper divisors (4173813207811).

221212100011121 is an equidigital number, since it uses as much as digits as its factorization.

221212100011121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4173813207810.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 221212100011121 its reverse (121110001212122), we get a palindrome (342322101223243).

The spelling of 221212100011121 in words is "two hundred twenty-one trillion, two hundred twelve billion, one hundred million, eleven thousand, one hundred twenty-one".