21313203217 has 2 divisors, whose sum is σ = 21313203218. Its totient is φ = 21313203216.

The previous prime is 21313203199. The next prime is 21313203221. The reversal of 21313203217 is 71230231312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19713283216 + 1599920001 = 140404^2 + 39999^2 .

It is a cyclic number.

It is not a de Polignac number, because 21313203217 - 2²⁷ = 21178985489 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21313203191 and 21313203200.

It is not a weakly prime, because it can be changed into another prime (21313203617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656601608 + 10656601609.

It is an arithmetic number, because the mean of its divisors is an integer number (10656601609).

Almost surely, 2^21313203217 is an apocalyptic number.

It is an amenable number.

21313203217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21313203217 is an equidigital number, since it uses as much as digits as its factorization.

21313203217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 25.

Adding to 21313203217 its reverse (71230231312), we get a palindrome (92543434529).

The spelling of 21313203217 in words is "twenty-one billion, three hundred thirteen million, two hundred three thousand, two hundred seventeen".