21210021212121 has 48 divisors (see below), whose sum is σ = 35361381444480. Its totient is φ = 11999555193600.

The previous prime is 21210021212089. The next prime is 21210021212123. The reversal of 21210021212121 is 12121212001212.

21210021212121 is a `hidden beast` number, since 212 + 100 + 21 + 212 + 121 = 666.

It is not a de Polignac number, because 21210021212121 - 2⁵ = 21210021212089 is a prime.

21210021212121 is a modest number, since divided by 21212121 gives 212100 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 21210021212094 and 21210021212103.

It is not an unprimeable number, because it can be changed into a prime (21210021212123) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 236270581 + ... + 236360333.

It is an arithmetic number, because the mean of its divisors is an integer number (736695446760).

Almost surely, 2^{21210021212121} is an apocalyptic number.

21210021212121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21210021212121 is a deficient number, since it is larger than the sum of its proper divisors (14151360232359).

21210021212121 is a wasteful number, since it uses less digits than its factorization.

21210021212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127006 (or 127003 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21210021212121 its reverse (12121212001212), we get a palindrome (33331233213333).

The spelling of 21210021212121 in words is "twenty-one trillion, two hundred ten billion, twenty-one million, two hundred twelve thousand, one hundred twenty-one".