21211212012221 has 32 divisors (see below), whose sum is σ = 27868153890816. Its totient is φ = 15653068200000.

The previous prime is 21211212012187. The next prime is 21211212012283. The reversal of 21211212012221 is 12221021211212.

It is not a de Polignac number, because 21211212012221 - 2⁶ = 21211212012157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21211212012193 and 21211212012202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211212012521) 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, 59113055 + ... + 59470796.

It is an arithmetic number, because the mean of its divisors is an integer number (870879809088).

Almost surely, 2^{21211212012221} is an apocalyptic number.

It is an amenable number.

21211212012221 is a deficient number, since it is larger than the sum of its proper divisors (6656941878595).

21211212012221 is a wasteful number, since it uses less digits than its factorization.

21211212012221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118583993.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21211212012221 its reverse (12221021211212), we get a palindrome (33432233223433).

The spelling of 21211212012221 in words is "twenty-one trillion, two hundred eleven billion, two hundred twelve million, twelve thousand, two hundred twenty-one".