100645 has 4 divisors (see below), whose sum is σ = 120780. Its totient is φ = 80512.
The previous prime is 100621. The next prime is 100649. The reversal of 100645 is 546001.
It is a semiprime because it is the product of two primes.
It can be written as a sum of positive squares in 2 ways, for example, as 66049 + 34596 = 257^2 + 186^2 .
It is a cyclic number.
It is not a de Polignac number, because 100645 - 25 = 100613 is a prime.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (100649) 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 3 ways as a sum of consecutive naturals, for example, 10060 + ... + 10069.
It is an arithmetic number, because the mean of its divisors is an integer number (30195).
2100645 is an apocalyptic number.
It is an amenable number.
100645 is a deficient number, since it is larger than the sum of its proper divisors (20135).
100645 is an equidigital number, since it uses as much as digits as its factorization.
100645 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 20134.
The product of its (nonzero) digits is 120, while the sum is 16.
The square root of 100645 is about 317.2459613612. The cubic root of 100645 is about 46.5154687041.
Adding to 100645 its reverse (546001), we get a palindrome (646646).
The spelling of 100645 in words is "one hundred thousand, six hundred forty-five".
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