208861 has 4 divisors (see below), whose sum is σ = 209824. Its totient is φ = 207900.

The previous prime is 208843. The next prime is 208877. The reversal of 208861 is 168802.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 168802 = 2 ⋅84401.

It is a cyclic number.

It is not a de Polignac number, because 208861 - 2¹¹ = 206813 is a prime.

It is a super-3 number, since 3×208861³ = 27333378403744143, which contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (208891) 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 3 ways as a sum of consecutive naturals, for example, 16 + ... + 646.

It is an arithmetic number, because the mean of its divisors is an integer number (52456).

2²⁰⁸⁸⁶¹ is an apocalyptic number.

It is an amenable number.

208861 is a deficient number, since it is larger than the sum of its proper divisors (963).

208861 is an equidigital number, since it uses as much as digits as its factorization.

208861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 962.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 208861 is about 457.0131289143. The cubic root of 208861 is about 59.3315623200.

The spelling of 208861 in words is "two hundred eight thousand, eight hundred sixty-one".