21121022121 has 32 divisors (see below), whose sum is σ = 29069967360. Its totient is φ = 13632105600.

The previous prime is 21121022119. The next prime is 21121022177. The reversal of 21121022121 is 12122012112.

It is not a de Polignac number, because 21121022121 - 2¹ = 21121022119 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21121022121.

It is not an unprimeable number, because it can be changed into a prime (21121002121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9432120 + ... + 9434358.

It is an arithmetic number, because the mean of its divisors is an integer number (908436480).

Almost surely, 2^21121022121 is an apocalyptic number.

It is an amenable number.

21121022121 is a deficient number, since it is larger than the sum of its proper divisors (7948945239).

21121022121 is a wasteful number, since it uses less digits than its factorization.

21121022121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2837.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21121022121 its reverse (12122012112), we get a palindrome (33243034233).

The spelling of 21121022121 in words is "twenty-one billion, one hundred twenty-one million, twenty-two thousand, one hundred twenty-one".