1001211001 has 4 divisors (see below), whose sum is σ = 1144241152. Its totient is φ = 858180852.

The previous prime is 1001210981. The next prime is 1001211017. The reversal of 1001211001 is 1001121001.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1001121001 = 19 ⋅52690579.

It is a cyclic number.

It is not a de Polignac number, because 1001211001 - 2¹⁷ = 1001079929 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (7), and also a Moran number because the ratio is a prime number: 143030143 = 1001211001 / (1 + 0 + 0 + 1 + 2 + 1 + 1 + 0 + 0 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1001214001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71515065 + ... + 71515078.

It is an arithmetic number, because the mean of its divisors is an integer number (286060288).

Almost surely, 2^1001211001 is an apocalyptic number.

It is an amenable number.

1001211001 is a deficient number, since it is larger than the sum of its proper divisors (143030151).

1001211001 is an equidigital number, since it uses as much as digits as its factorization.

1001211001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143030150.

The product of its (nonzero) digits is 2, while the sum is 7.

The square root of 1001211001 is about 31641.9184152921. The cubic root of 1001211001 is about 1000.4035041625.

Adding to 1001211001 its reverse (1001121001), we get a palindrome (2002332002).

Subtracting from 1001211001 its reverse (1001121001), we obtain a square (90000 = 300²).

The spelling of 1001211001 in words is "one billion, one million, two hundred eleven thousand, one".