100905 has 24 divisors (see below), whose sum is σ = 190656. Its totient is φ = 44640.

The previous prime is 100853. The next prime is 100907. The reversal of 100905 is 509001.

It is not a de Polignac number, because 100905 - 2⁸ = 100649 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (100907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3240 + ... + 3270.

It is an arithmetic number, because the mean of its divisors is an integer number (7944).

2¹⁰⁰⁹⁰⁵ is an apocalyptic number.

100905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

100905 is a deficient number, since it is larger than the sum of its proper divisors (89751).

100905 is an equidigital number, since it uses as much as digits as its factorization.

100905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 45, while the sum is 15.

The square root of 100905 is about 317.6554737447. The cubic root of 100905 is about 46.5554893128. Note that the first 3 decimals are identical.

Adding to 100905 its reverse (509001), we get a palindrome (609906).

The spelling of 100905 in words is "one hundred thousand, nine hundred five".