21100200221 has 4 divisors (see below), whose sum is σ = 21101165952. Its totient is φ = 21099234492.

The previous prime is 21100200217. The next prime is 21100200223. The reversal of 21100200221 is 12200200112.

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 21100200221 - 2² = 21100200217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100200223) 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, 449315 + ... + 494048.

It is an arithmetic number, because the mean of its divisors is an integer number (5275291488).

Almost surely, 2^21100200221 is an apocalyptic number.

It is an amenable number.

21100200221 is a deficient number, since it is larger than the sum of its proper divisors (965731).

21100200221 is an equidigital number, since it uses as much as digits as its factorization.

21100200221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 965730.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21100200221 its reverse (12200200112), we get a palindrome (33300400333).

The spelling of 21100200221 in words is "twenty-one billion, one hundred million, two hundred thousand, two hundred twenty-one".