9001 has 2 divisors, whose sum is σ = 9002. Its totient is φ = 9000.

The previous prime is 8999. The next prime is 9007. The reversal of 9001 is 1009.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6400 + 2601 = 80^2 + 51^2 .

It is an emirp because it is prime and its reverse (1009) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9001 - 2¹ = 8999 is a prime.

Together with 8999, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 14.

It is not a weakly prime, because it can be changed into another prime (9007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4500 + 4501.

It is an arithmetic number, because the mean of its divisors is an integer number (4501).

2⁹⁰⁰¹ is an apocalyptic number.

It is an amenable number.

9001 is a deficient number, since it is larger than the sum of its proper divisors (1).

9001 is an equidigital number, since it uses as much as digits as its factorization.

9001 is an evil number, because the sum of its binary digits is even.

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

The square root of 9001 is about 94.8736001214. The cubic root of 9001 is about 20.8016086034.

The spelling of 9001 in words is "nine thousand, one".