21100000217 has 4 divisors (see below), whose sum is σ = 21123951156. Its totient is φ = 21076049280.

The previous prime is 21100000157. The next prime is 21100000219. The reversal of 21100000217 is 71200000112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1291971136 + 19808029081 = 35944^2 + 140741^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100000217 - 2¹² = 21099996121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21100000219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11974148 + ... + 11975909.

It is an arithmetic number, because the mean of its divisors is an integer number (5280987789).

Almost surely, 2^21100000217 is an apocalyptic number.

It is an amenable number.

21100000217 is a deficient number, since it is larger than the sum of its proper divisors (23950939).

21100000217 is an equidigital number, since it uses as much as digits as its factorization.

21100000217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23950938.

The product of its (nonzero) digits is 28, while the sum is 14.

Adding to 21100000217 its reverse (71200000112), we get a palindrome (92300000329).

The spelling of 21100000217 in words is "twenty-one billion, one hundred million, two hundred seventeen", and thus it is an aban number.