221212121122221 has 16 divisors (see below), whose sum is σ = 310473660249600. Its totient is φ = 139712690094768.

The previous prime is 221212121122211. The next prime is 221212121122331. The reversal of 221212121122221 is 122221121212122.

It is not a de Polignac number, because 221212121122221 - 2²² = 221212116927917 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221212121122191 and 221212121122200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212121122211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36238320 + ... + 41900358.

It is an arithmetic number, because the mean of its divisors is an integer number (19404603765600).

Almost surely, 2^{221212121122221} is an apocalyptic number.

It is an amenable number.

221212121122221 is a deficient number, since it is larger than the sum of its proper divisors (89261539127379).

221212121122221 is a wasteful number, since it uses less digits than its factorization.

221212121122221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6347488.

The product of its digits is 512, while the sum is 24.

Adding to 221212121122221 its reverse (122221121212122), we get a palindrome (343433242334343).

The spelling of 221212121122221 in words is "two hundred twenty-one trillion, two hundred twelve billion, one hundred twenty-one million, one hundred twenty-two thousand, two hundred twenty-one".