201001001 has 4 divisors (see below), whose sum is σ = 207932100. Its totient is φ = 194069904.

The previous prime is 201000997. The next prime is 201001007. The reversal of 201001001 is 100100102.

It is a happy number.

201001001 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.

It can be written as a sum of positive squares in 2 ways, for example, as 102495376 + 98505625 = 10124^2 + 9925^2 .

It is a cyclic number.

It is not a de Polignac number, because 201001001 - 2² = 201000997 is a prime.

It is a Duffinian number.

201001001 is a modest number, since divided by 1001 gives 201 as remainder.

It is not an unprimeable number, because it can be changed into a prime (201001007) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3465506 + ... + 3465563.

It is an arithmetic number, because the mean of its divisors is an integer number (51983025).

Almost surely, 2^201001001 is an apocalyptic number.

It is an amenable number.

201001001 is a deficient number, since it is larger than the sum of its proper divisors (6931099).

201001001 is an equidigital number, since it uses as much as digits as its factorization.

201001001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6931098.

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 201001001 is about 14177.4821812619. The cubic root of 201001001 is about 585.7775726720. Note that the first 3 decimals are identical.

Adding to 201001001 its reverse (100100102), we get a palindrome (301101103).

The spelling of 201001001 in words is "two hundred one million, one thousand, one".