221200001022121 has 12 divisors (see below), whose sum is σ = 245544490142532. Its totient is φ = 199099910900000.

The previous prime is 221200001022073. The next prime is 221200001022197. The reversal of 221200001022121 is 121220100002122.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 162481190669721 + 58718810352400 = 12746811^2 + 7662820^2 .

It is a de Polignac number, because none of the positive numbers 2^k-221200001022121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221200001022095 and 221200001022104.

It is not an unprimeable number, because it can be changed into a prime (221200001029121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9049983730 + ... + 9050008171.

It is an arithmetic number, because the mean of its divisors is an integer number (20462040845211).

Almost surely, 2^{221200001022121} is an apocalyptic number.

It is an amenable number.

221200001022121 is a deficient number, since it is larger than the sum of its proper divisors (24344489120411).

221200001022121 is a wasteful number, since it uses less digits than its factorization.

221200001022121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18099992024 (or 18099992013 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 221200001022121 its reverse (121220100002122), we get a palindrome (342420101024243).

The spelling of 221200001022121 in words is "two hundred twenty-one trillion, two hundred billion, one million, twenty-two thousand, one hundred twenty-one".