100861 has 6 divisors (see below), whose sum is σ = 107450. Its totient is φ = 94656.

The previous prime is 100853. The next prime is 100907. The reversal of 100861 is 168001.

It can be written as a sum of positive squares in 3 ways, for example, as 52900 + 47961 = 230^2 + 219^2 .

It is not a de Polignac number, because 100861 - 2³ = 100853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 115 + ... + 463.

2¹⁰⁰⁸⁶¹ is an apocalyptic number.

It is an amenable number.

100861 is a deficient number, since it is larger than the sum of its proper divisors (6589).

100861 is an equidigital number, since it uses as much as digits as its factorization.

100861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383 (or 366 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 100861 is about 317.5862087686. The cubic root of 100861 is about 46.5487214310.

Adding to 100861 its reverse (168001), we get a palindrome (268862).

It can be divided in two parts, 100 and 861, that added together give a square (961 = 31²).

The spelling of 100861 in words is "one hundred thousand, eight hundred sixty-one".