221609173117 has 2 divisors, whose sum is σ = 221609173118. Its totient is φ = 221609173116.

The previous prime is 221609172949. The next prime is 221609173127. The reversal of 221609173117 is 711371906122.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 216107835876 + 5501337241 = 464874^2 + 74171^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221609173117 is a prime.

It is a super-2 number, since 2×221609173117² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 221609173117.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221609173127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110804586558 + 110804586559.

It is an arithmetic number, because the mean of its divisors is an integer number (110804586559).

Almost surely, 2^221609173117 is an apocalyptic number.

It is an amenable number.

221609173117 is a deficient number, since it is larger than the sum of its proper divisors (1).

221609173117 is an equidigital number, since it uses as much as digits as its factorization.

221609173117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31752, while the sum is 40.

The spelling of 221609173117 in words is "two hundred twenty-one billion, six hundred nine million, one hundred seventy-three thousand, one hundred seventeen".