21221012213 has 2 divisors, whose sum is σ = 21221012214. Its totient is φ = 21221012212.

The previous prime is 21221012209. The next prime is 21221012251. The reversal of 21221012213 is 31221012212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11495699524 + 9725312689 = 107218^2 + 98617^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221012213 - 2² = 21221012209 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21221012191 and 21221012200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221012413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610506106 + 10610506107.

It is an arithmetic number, because the mean of its divisors is an integer number (10610506107).

Almost surely, 2^21221012213 is an apocalyptic number.

It is an amenable number.

21221012213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221012213 is an equidigital number, since it uses as much as digits as its factorization.

21221012213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21221012213 its reverse (31221012212), we get a palindrome (52442024425).

Subtracting 21221012213 from its reverse (31221012212), we obtain a palindrome (9999999999).

The spelling of 21221012213 in words is "twenty-one billion, two hundred twenty-one million, twelve thousand, two hundred thirteen".