21210021002121 has 16 divisors (see below), whose sum is σ = 32345301811200. Its totient is φ = 12110535823248.

The previous prime is 21210021002101. The next prime is 21210021002171. The reversal of 21210021002121 is 12120012001212.

It is not a de Polignac number, because 21210021002121 - 2⁶ = 21210021002057 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210021002121.

It is not an unprimeable number, because it can be changed into a prime (21210021002101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 394813251 + ... + 394866968.

It is an arithmetic number, because the mean of its divisors is an integer number (2021581363200).

Almost surely, 2^{21210021002121} is an apocalyptic number.

21210021002121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21210021002121 is a deficient number, since it is larger than the sum of its proper divisors (11135280809079).

21210021002121 is a wasteful number, since it uses less digits than its factorization.

21210021002121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 789681508.

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

Adding to 21210021002121 its reverse (12120012001212), we get a palindrome (33330033003333).

Subtracting from 21210021002121 its reverse (12120012001212), we obtain a palindrome (9090009000909).

The spelling of 21210021002121 in words is "twenty-one trillion, two hundred ten billion, twenty-one million, two thousand, one hundred twenty-one".