21001200217 has 2 divisors, whose sum is σ = 21001200218. Its totient is φ = 21001200216.

The previous prime is 21001200191. The next prime is 21001200221. The reversal of 21001200217 is 71200210012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16778279961 + 4222920256 = 129531^2 + 64984^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001200217 - 2⁷ = 21001200089 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21001200217.

It is not a weakly prime, because it can be changed into another prime (21001200287) 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 as a sum of consecutive naturals, namely, 10500600108 + 10500600109.

It is an arithmetic number, because the mean of its divisors is an integer number (10500600109).

Almost surely, 2^21001200217 is an apocalyptic number.

It is an amenable number.

21001200217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001200217 is an equidigital number, since it uses as much as digits as its factorization.

21001200217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56, while the sum is 16.

Adding to 21001200217 its reverse (71200210012), we get a palindrome (92201410229).

The spelling of 21001200217 in words is "twenty-one billion, one million, two hundred thousand, two hundred seventeen".