21222202221 has 72 divisors (see below), whose sum is σ = 34797093240. Its totient is φ = 12444917760.

The previous prime is 21222202207. The next prime is 21222202223. The reversal of 21222202221 is 12220222212.

21222202221 is a `hidden beast` number, since 21 + 222 + 202 + 221 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 10532916900 + 10689285321 = 102630^2 + 103389^2 .

It is not a de Polignac number, because 21222202221 - 2¹³ = 21222194029 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21222202194 and 21222202203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222202223) 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 71 ways as a sum of consecutive naturals, for example, 7775185 + ... + 7777913.

Almost surely, 2^21222202221 is an apocalyptic number.

It is an amenable number.

21222202221 is a deficient number, since it is larger than the sum of its proper divisors (13574891019).

21222202221 is a wasteful number, since it uses less digits than its factorization.

21222202221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2987 (or 2973 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21222202221 its reverse (12220222212), we get a palindrome (33442424433).

The spelling of 21222202221 in words is "twenty-one billion, two hundred twenty-two million, two hundred two thousand, two hundred twenty-one".