221665005 has 20 divisors (see below), whose sum is σ = 397355772. Its totient is φ = 118221120.

The previous prime is 221664997. The next prime is 221665013. The reversal of 221665005 is 500566122.

221665005 is a `hidden beast` number, since 2 + 2 + 1 + 6 + 650 + 0 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (221664997) and next prime (221665013).

It can be written as a sum of positive squares in 2 ways, for example, as 158080329 + 63584676 = 12573^2 + 7974^2 .

It is not a de Polignac number, because 221665005 - 2³ = 221664997 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 221665005.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 273256 + ... + 274065.

Almost surely, 2^221665005 is an apocalyptic number.

It is an amenable number.

221665005 is a deficient number, since it is larger than the sum of its proper divisors (175690767).

221665005 is an equidigital number, since it uses as much as digits as its factorization.

221665005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 547338 (or 547329 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 221665005 is about 14888.4184855209. The cubic root of 221665005 is about 605.2001750926.

The spelling of 221665005 in words is "two hundred twenty-one million, six hundred sixty-five thousand, five".