20885221 has 6 divisors (see below), whose sum is σ = 24295110. Its totient is φ = 17901576.

The previous prime is 20885213. The next prime is 20885243. The reversal of 20885221 is 12258802.

It can be written as a sum of positive squares in only one way, i.e., 10962721 + 9922500 = 3311^2 + 3150^2 .

It is not a de Polignac number, because 20885221 - 2³ = 20885213 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20885221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20885201) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 213066 + ... + 213163.

It is an arithmetic number, because the mean of its divisors is an integer number (4049185).

Almost surely, 2^20885221 is an apocalyptic number.

It is an amenable number.

20885221 is a deficient number, since it is larger than the sum of its proper divisors (3409889).

20885221 is an equidigital number, since it uses as much as digits as its factorization.

20885221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426243 (or 426236 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 28.

The square root of 20885221 is about 4570.0351202152. The cubic root of 20885221 is about 275.3888537531.

The spelling of 20885221 in words is "twenty million, eight hundred eighty-five thousand, two hundred twenty-one".