21011102209 has 4 divisors (see below), whose sum is σ = 21924628416. Its totient is φ = 20097576004.

The previous prime is 21011102191. The next prime is 21011102219. The reversal of 21011102209 is 90220111012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21011102209 - 2⁹ = 21011101697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21011102219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 456763069 + ... + 456763114.

It is an arithmetic number, because the mean of its divisors is an integer number (5481157104).

Almost surely, 2^21011102209 is an apocalyptic number.

It is an amenable number.

21011102209 is a deficient number, since it is larger than the sum of its proper divisors (913526207).

21011102209 is an equidigital number, since it uses as much as digits as its factorization.

21011102209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 913526206.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 21011102209 in words is "twenty-one billion, eleven million, one hundred two thousand, two hundred nine".