21120220121 has 16 divisors (see below), whose sum is σ = 28357219968. Its totient is φ = 15191366400.

The previous prime is 21120220117. The next prime is 21120220129. The reversal of 21120220121 is 12102202112.

It is not a de Polignac number, because 21120220121 - 2² = 21120220117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120220096 and 21120220105.

It is not an unprimeable number, because it can be changed into a prime (21120220129) 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 15 ways as a sum of consecutive naturals, for example, 10548560 + ... + 10550561.

It is an arithmetic number, because the mean of its divisors is an integer number (1772326248).

Almost surely, 2^21120220121 is an apocalyptic number.

It is an amenable number.

21120220121 is a deficient number, since it is larger than the sum of its proper divisors (7236999847).

21120220121 is a wasteful number, since it uses less digits than its factorization.

21120220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21099152.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21120220121 its reverse (12102202112), we get a palindrome (33222422233).

The spelling of 21120220121 in words is "twenty-one billion, one hundred twenty million, two hundred twenty thousand, one hundred twenty-one".