21012222112221 has 16 divisors (see below), whose sum is σ = 29495388923840. Its totient is φ = 13268829231360.

The previous prime is 21012222112181. The next prime is 21012222112241. The reversal of 21012222112221 is 12221122221012.

It is not a de Polignac number, because 21012222112221 - 2³⁴ = 20995042243037 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012222112241) 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, 28070290 + ... + 28809123.

It is an arithmetic number, because the mean of its divisors is an integer number (1843461807740).

Almost surely, 2^{21012222112221} is an apocalyptic number.

It is an amenable number.

21012222112221 is a deficient number, since it is larger than the sum of its proper divisors (8483166811619).

21012222112221 is a wasteful number, since it uses less digits than its factorization.

21012222112221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56885916.

The product of its (nonzero) digits is 256, while the sum is 21.

Adding to 21012222112221 its reverse (12221122221012), we get a palindrome (33233344333233).

The spelling of 21012222112221 in words is "twenty-one trillion, twelve billion, two hundred twenty-two million, one hundred twelve thousand, two hundred twenty-one".