21101212222009 has 2 divisors, whose sum is σ = 21101212222010. Its totient is φ = 21101212222008.

The previous prime is 21101212222003. The next prime is 21101212222043. The reversal of 21101212222009 is 90022221210112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15508119661225 + 5593092560784 = 3938035^2 + 2364972^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101212222009 - 2⁹ = 21101212221497 is a prime.

It is a super-2 number, since 2×21101212222009² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21101212222003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550606111004 + 10550606111005.

It is an arithmetic number, because the mean of its divisors is an integer number (10550606111005).

Almost surely, 2^{21101212222009} is an apocalyptic number.

It is an amenable number.

21101212222009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101212222009 is an equidigital number, since it uses as much as digits as its factorization.

21101212222009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 25.

The spelling of 21101212222009 in words is "twenty-one trillion, one hundred one billion, two hundred twelve million, two hundred twenty-two thousand, nine".