208986561 has 24 divisors (see below), whose sum is σ = 357774144. Its totient is φ = 119419920.

The previous prime is 208986541. The next prime is 208986563. The reversal of 208986561 is 165689802.

208986561 is a `hidden beast` number, since 2 + 0 + 8 + 9 + 86 + 561 = 666.

It is not a de Polignac number, because 208986561 - 2¹⁰ = 208985537 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (208986563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 59730 + ... + 63131.

It is an arithmetic number, because the mean of its divisors is an integer number (14907256).

Almost surely, 2^208986561 is an apocalyptic number.

208986561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

208986561 is a deficient number, since it is larger than the sum of its proper divisors (148787583).

208986561 is an equidigital number, since it uses as much as digits as its factorization.

208986561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122883 (or 122871 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The square root of 208986561 is about 14456.3674897949. The cubic root of 208986561 is about 593.4344939314.

The spelling of 208986561 in words is "two hundred eight million, nine hundred eighty-six thousand, five hundred sixty-one".