21022232221 has 2 divisors, whose sum is σ = 21022232222. Its totient is φ = 21022232220.

The previous prime is 21022232201. The next prime is 21022232227. The reversal of 21022232221 is 12223222012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14917935321 + 6104296900 = 122139^2 + 78130^2 .

It is a cyclic number.

It is not a de Polignac number, because 21022232221 - 2¹⁹ = 21021707933 is a prime.

It is a super-3 number, since 3×21022232221³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21022232227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511116110 + 10511116111.

It is an arithmetic number, because the mean of its divisors is an integer number (10511116111).

Almost surely, 2^21022232221 is an apocalyptic number.

It is an amenable number.

21022232221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022232221 is an equidigital number, since it uses as much as digits as its factorization.

21022232221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21022232221 its reverse (12223222012), we get a palindrome (33245454233).

The spelling of 21022232221 in words is "twenty-one billion, twenty-two million, two hundred thirty-two thousand, two hundred twenty-one".