21217016620727 has 2 divisors, whose sum is σ = 21217016620728. Its totient is φ = 21217016620726.

The previous prime is 21217016620711. The next prime is 21217016620841. The reversal of 21217016620727 is 72702661071212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21217016620727 - 2⁴ = 21217016620711 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21217016650727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608508310363 + 10608508310364.

It is an arithmetic number, because the mean of its divisors is an integer number (10608508310364).

Almost surely, 2^{21217016620727} is an apocalyptic number.

21217016620727 is a deficient number, since it is larger than the sum of its proper divisors (1).

21217016620727 is an equidigital number, since it uses as much as digits as its factorization.

21217016620727 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 197568, while the sum is 44.

Adding to 21217016620727 its reverse (72702661071212), we get a palindrome (93919677691939).

The spelling of 21217016620727 in words is "twenty-one trillion, two hundred seventeen billion, sixteen million, six hundred twenty thousand, seven hundred twenty-seven".