21121111002121 has 16 divisors (see below), whose sum is σ = 22981771782928. Its totient is φ = 19294184448000.

The previous prime is 21121111002091. The next prime is 21121111002157. The reversal of 21121111002121 is 12120011112112.

It can be written as a sum of positive squares in 8 ways, for example, as 1819463765625 + 19301647236496 = 1348875^2 + 4393364^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121111002121 - 2²⁵ = 21121077447689 is a prime.

It is a super-2 number, since 2×21121111002121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121111002095 and 21121111002104.

It is not an unprimeable number, because it can be changed into a prime (21121111008121) 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, 19524481 + ... + 20577841.

It is an arithmetic number, because the mean of its divisors is an integer number (1436360736433).

Almost surely, 2^{21121111002121} is an apocalyptic number.

It is an amenable number.

21121111002121 is a deficient number, since it is larger than the sum of its proper divisors (1860660780807).

21121111002121 is a wasteful number, since it uses less digits than its factorization.

21121111002121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1069372.

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

Adding to 21121111002121 its reverse (12120011112112), we get a palindrome (33241122114233).

The spelling of 21121111002121 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred eleven million, two thousand, one hundred twenty-one".