21220210212221 has 16 divisors (see below), whose sum is σ = 21728127102528. Its totient is φ = 20718020332800.

The previous prime is 21220210212211. The next prime is 21220210212233. The reversal of 21220210212221 is 12221201202212.

It is a cyclic number.

It is not a de Polignac number, because 21220210212221 - 2¹⁸ = 21220209950077 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21220210212193 and 21220210212202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220210212211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2162306 + ... + 6864108.

It is an arithmetic number, because the mean of its divisors is an integer number (1358007943908).

Almost surely, 2^{21220210212221} is an apocalyptic number.

It is an amenable number.

21220210212221 is a deficient number, since it is larger than the sum of its proper divisors (507916890307).

21220210212221 is a wasteful number, since it uses less digits than its factorization.

21220210212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4702412.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21220210212221 its reverse (12221201202212), we get a palindrome (33441411414433).

The spelling of 21220210212221 in words is "twenty-one trillion, two hundred twenty billion, two hundred ten million, two hundred twelve thousand, two hundred twenty-one".