21500340313 has 2 divisors, whose sum is σ = 21500340314. Its totient is φ = 21500340312.

The previous prime is 21500340287. The next prime is 21500340319. The reversal of 21500340313 is 31304300512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20508531264 + 991809049 = 143208^2 + 31493^2 .

It is a cyclic number.

It is not a de Polignac number, because 21500340313 - 2²¹ = 21498243161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21500340319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10750170156 + 10750170157.

It is an arithmetic number, because the mean of its divisors is an integer number (10750170157).

Almost surely, 2^21500340313 is an apocalyptic number.

It is an amenable number.

21500340313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21500340313 is an equidigital number, since it uses as much as digits as its factorization.

21500340313 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 22.

Adding to 21500340313 its reverse (31304300512), we get a palindrome (52804640825).

The spelling of 21500340313 in words is "twenty-one billion, five hundred million, three hundred forty thousand, three hundred thirteen".