21212010217 has 2 divisors, whose sum is σ = 21212010218. Its totient is φ = 21212010216.

The previous prime is 21212010187. The next prime is 21212010247. The reversal of 21212010217 is 71201021212.

It is a balanced prime because it is at equal distance from previous prime (21212010187) and next prime (21212010247).

It can be written as a sum of positive squares in only one way, i.e., 19127996416 + 2084013801 = 138304^2 + 45651^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21212010217 is a prime.

It is a super-2 number, since 2×21212010217² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21212010194 and 21212010203.

It is not a weakly prime, because it can be changed into another prime (21212010247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606005108 + 10606005109.

It is an arithmetic number, because the mean of its divisors is an integer number (10606005109).

Almost surely, 2^21212010217 is an apocalyptic number.

It is an amenable number.

21212010217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212010217 is an equidigital number, since it uses as much as digits as its factorization.

21212010217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112, while the sum is 19.

Adding to 21212010217 its reverse (71201021212), we get a palindrome (92413031429).

The spelling of 21212010217 in words is "twenty-one billion, two hundred twelve million, ten thousand, two hundred seventeen".