2001121001 has 4 divisors (see below), whose sum is σ = 2183041104. Its totient is φ = 1819200900.

The previous prime is 2001120973. The next prime is 2001121019. The reversal of 2001121001 is 1001211002.

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 a de Polignac number, because none of the positive numbers 2^k-2001121001 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2001121001.

It is not an unprimeable number, because it can be changed into a prime (2001121091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90960035 + ... + 90960056.

It is an arithmetic number, because the mean of its divisors is an integer number (545760276).

Almost surely, 2^2001121001 is an apocalyptic number.

It is an amenable number.

2001121001 is a deficient number, since it is larger than the sum of its proper divisors (181920103).

2001121001 is a wasteful number, since it uses less digits than its factorization.

2001121001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181920102.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 2001121001 is about 44733.8909664697. The cubic root of 2001121001 is about 1260.1564013883.

Adding to 2001121001 its reverse (1001211002), we get a palindrome (3002332003).

Subtracting from 2001121001 its reverse (1001211002), we obtain a palindrome (999909999).

The spelling of 2001121001 in words is "two billion, one million, one hundred twenty-one thousand, one".