21111010220121 has 32 divisors (see below), whose sum is σ = 29776656053760. Its totient is φ = 13267192041216.

The previous prime is 21111010220089. The next prime is 21111010220129. The reversal of 21111010220121 is 12102201011112.

It is a happy number.

It is not a de Polignac number, because 21111010220121 - 2⁵ = 21111010220089 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21111010220121.

It is not an unprimeable number, because it can be changed into a prime (21111010220129) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9244305 + ... + 11299521.

It is an arithmetic number, because the mean of its divisors is an integer number (930520501680).

Almost surely, 2^{21111010220121} is an apocalyptic number.

It is an amenable number.

21111010220121 is a deficient number, since it is larger than the sum of its proper divisors (8665645833639).

21111010220121 is a wasteful number, since it uses less digits than its factorization.

21111010220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2056133.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21111010220121 its reverse (12102201011112), we get a palindrome (33213211231233).

The spelling of 21111010220121 in words is "twenty-one trillion, one hundred eleven billion, ten million, two hundred twenty thousand, one hundred twenty-one".