21401200217 has 2 divisors, whose sum is σ = 21401200218. Its totient is φ = 21401200216.

The previous prime is 21401200211. The next prime is 21401200273. The reversal of 21401200217 is 71200210412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13297779856 + 8103420361 = 115316^2 + 90019^2 .

It is a cyclic number.

It is not a de Polignac number, because 21401200217 - 2²⁶ = 21334091353 is a prime.

It is a super-2 number, since 2×21401200217² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21401200211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700600108 + 10700600109.

It is an arithmetic number, because the mean of its divisors is an integer number (10700600109).

Almost surely, 2^21401200217 is an apocalyptic number.

It is an amenable number.

21401200217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21401200217 is an equidigital number, since it uses as much as digits as its factorization.

21401200217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 224, while the sum is 20.

Adding to 21401200217 its reverse (71200210412), we get a palindrome (92601410629).

The spelling of 21401200217 in words is "twenty-one billion, four hundred one million, two hundred thousand, two hundred seventeen".