221745878017 has 2 divisors, whose sum is σ = 221745878018. Its totient is φ = 221745878016.

The previous prime is 221745877993. The next prime is 221745878047. The reversal of 221745878017 is 710878547122.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 207971569521 + 13774308496 = 456039^2 + 117364^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221745878017 is a prime.

It is not a weakly prime, because it can be changed into another prime (221745878047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110872939008 + 110872939009.

It is an arithmetic number, because the mean of its divisors is an integer number (110872939009).

Almost surely, 2^221745878017 is an apocalyptic number.

It is an amenable number.

221745878017 is a deficient number, since it is larger than the sum of its proper divisors (1).

221745878017 is an equidigital number, since it uses as much as digits as its factorization.

221745878017 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1756160, while the sum is 52.

The spelling of 221745878017 in words is "two hundred twenty-one billion, seven hundred forty-five million, eight hundred seventy-eight thousand, seventeen".