21111005717 has 2 divisors, whose sum is σ = 21111005718. Its totient is φ = 21111005716.

The previous prime is 21111005693. The next prime is 21111005731. The reversal of 21111005717 is 71750011112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17196125956 + 3914879761 = 131134^2 + 62569^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111005717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111005767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555502858 + 10555502859.

It is an arithmetic number, because the mean of its divisors is an integer number (10555502859).

Almost surely, 2^21111005717 is an apocalyptic number.

It is an amenable number.

21111005717 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111005717 is an equidigital number, since it uses as much as digits as its factorization.

21111005717 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 490, while the sum is 26.

Adding to 21111005717 its reverse (71750011112), we get a palindrome (92861016829).

The spelling of 21111005717 in words is "twenty-one billion, one hundred eleven million, five thousand, seven hundred seventeen".