21707361517 has 2 divisors, whose sum is σ = 21707361518. Its totient is φ = 21707361516.

The previous prime is 21707361499. The next prime is 21707361569. The reversal of 21707361517 is 71516370712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13227530121 + 8479831396 = 115011^2 + 92086^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21707361517 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21707361517.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21707361917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10853680758 + 10853680759.

It is an arithmetic number, because the mean of its divisors is an integer number (10853680759).

Almost surely, 2^21707361517 is an apocalyptic number.

It is an amenable number.

21707361517 is a deficient number, since it is larger than the sum of its proper divisors (1).

21707361517 is an equidigital number, since it uses as much as digits as its factorization.

21707361517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 61740, while the sum is 40.

The spelling of 21707361517 in words is "twenty-one billion, seven hundred seven million, three hundred sixty-one thousand, five hundred seventeen".