21727375717 has 2 divisors, whose sum is σ = 21727375718. Its totient is φ = 21727375716.

The previous prime is 21727375699. The next prime is 21727375751. The reversal of 21727375717 is 71757372712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18519399396 + 3207976321 = 136086^2 + 56639^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21727375717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21727375757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10863687858 + 10863687859.

It is an arithmetic number, because the mean of its divisors is an integer number (10863687859).

Almost surely, 2^21727375717 is an apocalyptic number.

It is an amenable number.

21727375717 is a deficient number, since it is larger than the sum of its proper divisors (1).

21727375717 is an equidigital number, since it uses as much as digits as its factorization.

21727375717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008420, while the sum is 49.

The spelling of 21727375717 in words is "twenty-one billion, seven hundred twenty-seven million, three hundred seventy-five thousand, seven hundred seventeen".