217522560721 has 2 divisors, whose sum is σ = 217522560722. Its totient is φ = 217522560720.

The previous prime is 217522560709. The next prime is 217522560797. The reversal of 217522560721 is 127065225712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 217468332225 + 54228496 = 466335^2 + 7364^2 .

It is a cyclic number.

It is not a de Polignac number, because 217522560721 - 2⁹ = 217522560209 is a prime.

It is a super-2 number, since 2×217522560721² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (217522530721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108761280360 + 108761280361.

It is an arithmetic number, because the mean of its divisors is an integer number (108761280361).

Almost surely, 2^217522560721 is an apocalyptic number.

It is an amenable number.

217522560721 is a deficient number, since it is larger than the sum of its proper divisors (1).

217522560721 is an equidigital number, since it uses as much as digits as its factorization.

217522560721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 117600, while the sum is 40.

The spelling of 217522560721 in words is "two hundred seventeen billion, five hundred twenty-two million, five hundred sixty thousand, seven hundred twenty-one".