220005521 has 4 divisors (see below), whose sum is σ = 220082544. Its totient is φ = 219928500.

The previous prime is 220005497. The next prime is 220005523. The reversal of 220005521 is 125500022.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 125500022 = 2 ⋅62750011.

It is a cyclic number.

It is not a de Polignac number, because 220005521 - 2¹⁴ = 219989137 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 220005521.

It is not an unprimeable number, because it can be changed into a prime (220005523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34055 + ... + 39996.

It is an arithmetic number, because the mean of its divisors is an integer number (55020636).

Almost surely, 2^220005521 is an apocalyptic number.

It is an amenable number.

220005521 is a deficient number, since it is larger than the sum of its proper divisors (77023).

220005521 is an equidigital number, since it uses as much as digits as its factorization.

220005521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77022.

The product of its (nonzero) digits is 200, while the sum is 17.

The square root of 220005521 is about 14832.5830858957. The cubic root of 220005521 is about 603.6861235212.

Adding to 220005521 its reverse (125500022), we get a palindrome (345505543).

The spelling of 220005521 in words is "two hundred twenty million, five thousand, five hundred twenty-one".