221005505 has 32 divisors (see below), whose sum is σ = 317689344. Its totient is φ = 144308736.

The previous prime is 221005493. The next prime is 221005507. The reversal of 221005505 is 505500122.

It is a cyclic number.

It is not a de Polignac number, because 221005505 - 2⁶ = 221005441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221005507) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 235397 + ... + 236333.

It is an arithmetic number, because the mean of its divisors is an integer number (9927792).

Almost surely, 2^221005505 is an apocalyptic number.

It is an amenable number.

221005505 is a deficient number, since it is larger than the sum of its proper divisors (96683839).

221005505 is a wasteful number, since it uses less digits than its factorization.

221005505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1265.

The product of its (nonzero) digits is 500, while the sum is 20.

The square root of 221005505 is about 14866.2538993520. The cubic root of 221005505 is about 604.5993796078.

Adding to 221005505 its reverse (505500122), we get a palindrome (726505627).

The spelling of 221005505 in words is "two hundred twenty-one million, five thousand, five hundred five".