1001001 has 4 divisors (see below), whose sum is σ = 1334672.
Its totient is φ = 667332.
The previous prime is 1000999. The next prime is 1001003.
1001001 is nontrivially palindromic in base 10.
1001001 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.
It is an interprime number because it is at equal distance from previous prime (1000999) and next prime (1001003).
It is not a de Polignac number, because 1001001 - 21 = 1000999 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (3), and also a Moran number because the ratio is a prime number: 333667 = 1001001 / (1 + 0 + 0 + 1 + 0 + 0 + 1).
It is a D-number.
1001001 is a strobogrammatic number because it is the same when read upside-down.
It is the 1001-st Hogben number.
It is a Duffinian number.
1001001 is a modest number, since divided by 1001 gives 1 as remainder.
It is not an unprimeable number, because it can be changed into a prime (1001003) by changing a digit.
It is a nontrivial repunit in base 1000.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166831 + ... + 166836.
It is an arithmetic number, because the mean of its divisors is an integer number (333668).
21001001 is an apocalyptic number.
It is an amenable number.
1001001 is a deficient number, since it is larger than the sum of its proper divisors (333671).
1001001 is an equidigital number, since it uses as much as digits as its factorization.
1001001 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 333670.
The product of its (nonzero) digits is 1, while the sum is 3.
The square root of 1001001 is about 1000.5003748125.
The cubic root of 1001001 is about 100.0333555395.
The spelling of 1001001 in words is "one million, one thousand, one".