100009 has 12 divisors (see below), whose sum is σ = 126084. Its totient is φ = 78624.

The previous prime is 100003. The next prime is 100019. The reversal of 100009 is 900001.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21609 + 78400 = 147^2 + 280^2 .

It is not a de Polignac number, because 100009 - 2⁷ = 99881 is a prime.

100009 is a modest number, since divided by 9 gives 1 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 99968 and 100004.

It is not an unprimeable number, because it can be changed into a prime (100003) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 559 + ... + 715.

It is an arithmetic number, because the mean of its divisors is an integer number (10507).

2¹⁰⁰⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

100009 is a deficient number, since it is larger than the sum of its proper divisors (26075).

100009 is a wasteful number, since it uses less digits than its factorization.

100009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184 (or 177 counting only the distinct ones).

The product of its (nonzero) digits is 9, while the sum is 10.

The square root of 100009 is about 316.2419959461. The cubic root of 100009 is about 46.4172807710.

Subtracting from 100009 its sum of digits (10), we obtain a palindrome (99999).

It can be divided in two parts, 10000 and 9, that multiplied together give a square (90000 = 300²).

The spelling of 100009 in words is "one hundred thousand, nine".