1001 has 8 divisors (see below), whose sum is σ = 1344. Its totient is φ = 720.

The previous prime is 997. The next prime is 1009.

1001 = 4^{2} + 5^{2} + ... + 14^{2}.

1001 is nontrivially palindromic in base 10.

It is a Cunningham number, because it is equal to 10^{3}+1.

1001 is an esthetic number in base 6, because in such base its adjacent digits differ by 1.

1001 is a nontrivial binomial coefficient, being equal to C(14, 4).

It is a sliding number, since 1001 = 1 + 1000 and 1/1 + 1/1000 = 1.001.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1001 - 2^{2} = 997 is a prime.

It is a magnanimous number.

1001 is a strobogrammatic number because it is the same when read upside-down.

It is a Curzon number.

It is a plaindrome in base 15.

It is a nialpdrome in base 4 and base 11.

It is a junction number, because it is equal to *n*+sod(*n*) for *n* = 982 and 1000.

It is not an unprimeable number, because it can be changed into a prime (1009) 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 7 ways as a sum of consecutive naturals, for example, 71 + ... + 83.

It is an arithmetic number, because the mean of its divisors is an integer number (168).

1001 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1001 is the 26-th pentagonal number.

It is an amenable number.

1001 is a deficient number, since it is larger than the sum of its proper divisors (343).

1001 is a wasteful number, since it uses less digits than its factorization.

1001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31.

The product of its (nonzero) digits is 1, while the sum is 2.

The square root of 1001 is about 31.6385840391. The cubic root of 1001 is about 10.0033322228.

It can be divided in two parts, 100 and 1, that added together give a palindrome (101).

The spelling of 1001 in words is "one thousand, one", and thus it is an iban number.

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