21400203217 has 2 divisors, whose sum is σ = 21400203218. Its totient is φ = 21400203216.

The previous prime is 21400203203. The next prime is 21400203233. The reversal of 21400203217 is 71230200412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17446183056 + 3954020161 = 132084^2 + 62881^2 .

It is a cyclic number.

It is not a de Polignac number, because 21400203217 - 2¹¹ = 21400201169 is a prime.

It is not a weakly prime, because it can be changed into another prime (21400203277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700101608 + 10700101609.

It is an arithmetic number, because the mean of its divisors is an integer number (10700101609).

Almost surely, 2^21400203217 is an apocalyptic number.

It is an amenable number.

21400203217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21400203217 is an equidigital number, since it uses as much as digits as its factorization.

21400203217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 22.

Adding to 21400203217 its reverse (71230200412), we get a palindrome (92630403629).

The spelling of 21400203217 in words is "twenty-one billion, four hundred million, two hundred three thousand, two hundred seventeen".