100815 has 32 divisors (see below), whose sum is σ = 193536. Its totient is φ = 44160.

The previous prime is 100811. The next prime is 100823. The reversal of 100815 is 518001.

It is a happy number.

It is not a de Polignac number, because 100815 - 2² = 100811 is a prime.

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

It is an Ulam number.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 100794 and 100803.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 100815.

It is not an unprimeable number, because it can be changed into a prime (100811) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2122 + ... + 2168.

It is an arithmetic number, because the mean of its divisors is an integer number (6048).

2¹⁰⁰⁸¹⁵ is an apocalyptic number.

100815 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

100815 is a deficient number, since it is larger than the sum of its proper divisors (92721).

100815 is a wasteful number, since it uses less digits than its factorization.

100815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79.

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

The square root of 100815 is about 317.5137792286. The cubic root of 100815 is about 46.5416438133.

Adding to 100815 its reverse (518001), we get a palindrome (618816).

It can be divided in two parts, 10081 and 5, that multiplied together give a palindrome (50405).

The spelling of 100815 in words is "one hundred thousand, eight hundred fifteen".