221221111112121 has 4 divisors (see below), whose sum is σ = 294961481482832. Its totient is φ = 147480740741412.

The previous prime is 221221111112083. The next prime is 221221111112159. The reversal of 221221111112121 is 121211111122122.

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 an interprime number because it is at equal distance from previous prime (221221111112083) and next prime (221221111112159).

It is not a de Polignac number, because 221221111112121 - 2¹⁰ = 221221111111097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221221111112191) 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, 36870185185351 + ... + 36870185185356.

It is an arithmetic number, because the mean of its divisors is an integer number (73740370370708).

Almost surely, 2^{221221111112121} is an apocalyptic number.

It is an amenable number.

221221111112121 is a deficient number, since it is larger than the sum of its proper divisors (73740370370711).

221221111112121 is an equidigital number, since it uses as much as digits as its factorization.

221221111112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73740370370710.

The product of its digits is 64, while the sum is 21.

Adding to 221221111112121 its reverse (121211111122122), we get a palindrome (342432222234243).

The spelling of 221221111112121 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred twelve thousand, one hundred twenty-one".