21210022221 has 8 divisors (see below), whose sum is σ = 29768452320. Its totient is φ = 13395803472.

The previous prime is 21210022213. The next prime is 21210022237. The reversal of 21210022221 is 12222001212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21210022221 - 2³ = 21210022213 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210022221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210022241) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 186052770 + ... + 186052883.

It is an arithmetic number, because the mean of its divisors is an integer number (3721056540).

Almost surely, 2^21210022221 is an apocalyptic number.

It is an amenable number.

21210022221 is a deficient number, since it is larger than the sum of its proper divisors (8558430099).

21210022221 is a wasteful number, since it uses less digits than its factorization.

21210022221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372105675.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21210022221 its reverse (12222001212), we get a palindrome (33432023433).

The spelling of 21210022221 in words is "twenty-one billion, two hundred ten million, twenty-two thousand, two hundred twenty-one".