21220040121 has 16 divisors (see below), whose sum is σ = 32649237504. Its totient is φ = 12008010384.

The previous prime is 21220040099. The next prime is 21220040129. The reversal of 21220040121 is 12104002212.

It is not a de Polignac number, because 21220040121 - 2⁹ = 21220039609 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21220040121.

It is not an unprimeable number, because it can be changed into a prime (21220040129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4903071 + ... + 4907396.

It is an arithmetic number, because the mean of its divisors is an integer number (2040577344).

Almost surely, 2^21220040121 is an apocalyptic number.

21220040121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21220040121 is a deficient number, since it is larger than the sum of its proper divisors (11429197383).

21220040121 is a wasteful number, since it uses less digits than its factorization.

21220040121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9810580.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21220040121 its reverse (12104002212), we get a palindrome (33324042333).

The spelling of 21220040121 in words is "twenty-one billion, two hundred twenty million, forty thousand, one hundred twenty-one".