21272966717 has 2 divisors, whose sum is σ = 21272966718. Its totient is φ = 21272966716.

The previous prime is 21272966653. The next prime is 21272966747. The reversal of 21272966717 is 71766927212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16571670361 + 4701296356 = 128731^2 + 68566^2 .

It is a cyclic number.

It is not a de Polignac number, because 21272966717 - 2⁶ = 21272966653 is a prime.

It is a super-2 number, since 2×21272966717² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21272966747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10636483358 + 10636483359.

It is an arithmetic number, because the mean of its divisors is an integer number (10636483359).

Almost surely, 2^21272966717 is an apocalyptic number.

It is an amenable number.

21272966717 is a deficient number, since it is larger than the sum of its proper divisors (1).

21272966717 is an equidigital number, since it uses as much as digits as its factorization.

21272966717 is an evil number, because the sum of its binary digits is even.

The product of its digits is 889056, while the sum is 50.

The spelling of 21272966717 in words is "twenty-one billion, two hundred seventy-two million, nine hundred sixty-six thousand, seven hundred seventeen".