21011221200121 has 16 divisors (see below), whose sum is σ = 21969374768640. Its totient is φ = 20056827510720.

The previous prime is 21011221200107. The next prime is 21011221200133. The reversal of 21011221200121 is 12100212211012.

It is a cyclic number.

It is not a de Polignac number, because 21011221200121 - 2⁷ = 21011221199993 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21011221200095 and 21011221200104.

It is not an unprimeable number, because it can be changed into a prime (21011227200121) 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, 21929731 + ... + 22867783.

It is an arithmetic number, because the mean of its divisors is an integer number (1373085923040).

Almost surely, 2^{21011221200121} is an apocalyptic number.

It is an amenable number.

21011221200121 is a deficient number, since it is larger than the sum of its proper divisors (958153568519).

21011221200121 is a wasteful number, since it uses less digits than its factorization.

21011221200121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 940056.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21011221200121 its reverse (12100212211012), we get a palindrome (33111433411133).

The spelling of 21011221200121 in words is "twenty-one trillion, eleven billion, two hundred twenty-one million, two hundred thousand, one hundred twenty-one".