21212122229 has 2 divisors, whose sum is σ = 21212122230. Its totient is φ = 21212122228.

The previous prime is 21212122219. The next prime is 21212122247. The reversal of 21212122229 is 92222121212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17662941604 + 3549180625 = 132902^2 + 59575^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212122229 - 2¹⁶ = 21212056693 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21212122198 and 21212122207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212122219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606061114 + 10606061115.

It is an arithmetic number, because the mean of its divisors is an integer number (10606061115).

Almost surely, 2^21212122229 is an apocalyptic number.

It is an amenable number.

21212122229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212122229 is an equidigital number, since it uses as much as digits as its factorization.

21212122229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 26.

The spelling of 21212122229 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-two thousand, two hundred twenty-nine".