21210212012121 has 24 divisors (see below), whose sum is σ = 33580551120480. Its totient is φ = 12793751308800.

The previous prime is 21210212012117. The next prime is 21210212012147. The reversal of 21210212012121 is 12121021201212.

21210212012121 is a `hidden beast` number, since 21 + 210 + 21 + 201 + 212 + 1 = 666.

It is not a de Polignac number, because 21210212012121 - 2² = 21210212012117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210212012094 and 21210212012103.

It is not an unprimeable number, because it can be changed into a prime (21210212012921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 507667656 + ... + 507709433.

It is an arithmetic number, because the mean of its divisors is an integer number (1399189630020).

Almost surely, 2^{21210212012121} is an apocalyptic number.

It is an amenable number.

21210212012121 is a deficient number, since it is larger than the sum of its proper divisors (12370339108359).

21210212012121 is a wasteful number, since it uses less digits than its factorization.

21210212012121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1015377317 (or 1015377314 counting only the distinct ones).

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

Adding to 21210212012121 its reverse (12121021201212), we get a palindrome (33331233213333).

The spelling of 21210212012121 in words is "twenty-one trillion, two hundred ten billion, two hundred twelve million, twelve thousand, one hundred twenty-one".