21001120122121 has 16 divisors (see below), whose sum is σ = 21126937466880. Its totient is φ = 20875484897280.

The previous prime is 21001120122089. The next prime is 21001120122127. The reversal of 21001120122121 is 12122102110012.

It is a cyclic number.

It is not a de Polignac number, because 21001120122121 - 2⁵ = 21001120122089 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001120122095 and 21001120122104.

It is not an unprimeable number, because it can be changed into a prime (21001120122127) 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, 2038344856 + ... + 2038355158.

It is an arithmetic number, because the mean of its divisors is an integer number (1320433591680).

Almost surely, 2^{21001120122121} is an apocalyptic number.

It is an amenable number.

21001120122121 is a deficient number, since it is larger than the sum of its proper divisors (125817344759).

21001120122121 is a wasteful number, since it uses less digits than its factorization.

21001120122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17976.

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

Adding to 21001120122121 its reverse (12122102110012), we get a palindrome (33123222232133).

The spelling of 21001120122121 in words is "twenty-one trillion, one billion, one hundred twenty million, one hundred twenty-two thousand, one hundred twenty-one".