101805 has 16 divisors (see below), whose sum is σ = 177984. Its totient is φ = 49280.

The previous prime is 101797. The next prime is 101807. The reversal of 101805 is 508101.

It is a happy number.

It is not a de Polignac number, because 101805 - 2³ = 101797 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (101807) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 144 + ... + 473.

It is an arithmetic number, because the mean of its divisors is an integer number (11124).

2¹⁰¹⁸⁰⁵ is an apocalyptic number.

101805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

101805 is a deficient number, since it is larger than the sum of its proper divisors (76179).

101805 is a wasteful number, since it uses less digits than its factorization.

101805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636.

The product of its (nonzero) digits is 40, while the sum is 15.

The square root of 101805 is about 319.0689580639. The cubic root of 101805 is about 46.6934936455.

Adding to 101805 its reverse (508101), we get a palindrome (609906).

The spelling of 101805 in words is "one hundred one thousand, eight hundred five".