1001172021 has 4 divisors (see below), whose sum is σ = 1334896032. Its totient is φ = 667448012.

The previous prime is 1001172019. The next prime is 1001172031. The reversal of 1001172021 is 1202711001.

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 cyclic number.

It is not a de Polignac number, because 1001172021 - 2¹ = 1001172019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001172031) 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, 166862001 + ... + 166862006.

It is an arithmetic number, because the mean of its divisors is an integer number (333724008).

Almost surely, 2^1001172021 is an apocalyptic number.

It is an amenable number.

1001172021 is a deficient number, since it is larger than the sum of its proper divisors (333724011).

1001172021 is an equidigital number, since it uses as much as digits as its factorization.

1001172021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333724010.

The product of its (nonzero) digits is 28, while the sum is 15.

The square root of 1001172021 is about 31641.3024542290. The cubic root of 1001172021 is about 1000.3905211401.

Adding to 1001172021 its reverse (1202711001), we get a palindrome (2203883022).

The spelling of 1001172021 in words is "one billion, one million, one hundred seventy-two thousand, twenty-one".