220021605 has 12 divisors (see below), whose sum is σ = 381370860. Its totient is φ = 117344832.

The previous prime is 220021567. The next prime is 220021631. The reversal of 220021605 is 506120022.

220021605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 68657796 + 151363809 = 8286^2 + 12303^2 .

It is not a de Polignac number, because 220021605 - 2¹⁵ = 219988837 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2444640 + ... + 2444729.

It is an arithmetic number, because the mean of its divisors is an integer number (31780905).

Almost surely, 2^220021605 is an apocalyptic number.

It is an amenable number.

220021605 is a deficient number, since it is larger than the sum of its proper divisors (161349255).

220021605 is a wasteful number, since it uses less digits than its factorization.

220021605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4889380 (or 4889377 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 220021605 is about 14833.1252607129. The cubic root of 220021605 is about 603.7008344414.

Adding to 220021605 its reverse (506120022), we get a palindrome (726141627).

The spelling of 220021605 in words is "two hundred twenty million, twenty-one thousand, six hundred five".