220686561 has 6 divisors (see below), whose sum is σ = 318769490. Its totient is φ = 147124368.

The previous prime is 220686553. The next prime is 220686563. The reversal of 220686561 is 165686022.

220686561 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 only one way, i.e., 220344336 + 342225 = 14844^2 + 585^2 .

It is not a de Polignac number, because 220686561 - 2³ = 220686553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (220686563) 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, 12260356 + ... + 12260373.

Almost surely, 2^220686561 is an apocalyptic number.

It is an amenable number.

220686561 is a deficient number, since it is larger than the sum of its proper divisors (98082929).

220686561 is a wasteful number, since it uses less digits than its factorization.

220686561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24520735 (or 24520732 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 220686561 is about 14855.5229123717. The cubic root of 220686561 is about 604.3083971404.

The spelling of 220686561 in words is "two hundred twenty million, six hundred eighty-six thousand, five hundred sixty-one".