21317211073 has 4 divisors (see below), whose sum is σ = 21319676500. Its totient is φ = 21314745648.

The previous prime is 21317211061. The next prime is 21317211077. The reversal of 21317211073 is 37011271312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2189491264 + 19127719809 = 46792^2 + 138303^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21317211073 is a prime.

It is a super-2 number, since 2×21317211073² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21317211077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1219698 + ... + 1237051.

It is an arithmetic number, because the mean of its divisors is an integer number (5329919125).

Almost surely, 2^21317211073 is an apocalyptic number.

It is an amenable number.

21317211073 is a deficient number, since it is larger than the sum of its proper divisors (2465427).

21317211073 is an equidigital number, since it uses as much as digits as its factorization.

21317211073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2465426.

The product of its (nonzero) digits is 1764, while the sum is 28.

Adding to 21317211073 its reverse (37011271312), we get a palindrome (58328482385).

The spelling of 21317211073 in words is "twenty-one billion, three hundred seventeen million, two hundred eleven thousand, seventy-three".