21001001003 has 8 divisors (see below), whose sum is σ = 21296960256. Its totient is φ = 20706768000.

The previous prime is 21001000991. The next prime is 21001001009. The reversal of 21001001003 is 30010010012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21001001003 - 2¹⁰ = 21000999979 is a prime.

It is a super-3 number, since 3×21001001003³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001001009) 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 7 ways as a sum of consecutive naturals, for example, 407051 + ... + 455732.

It is an arithmetic number, because the mean of its divisors is an integer number (2662120032).

Almost surely, 2^21001001003 is an apocalyptic number.

21001001003 is a deficient number, since it is larger than the sum of its proper divisors (295959253).

21001001003 is a wasteful number, since it uses less digits than its factorization.

21001001003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 863125.

The product of its (nonzero) digits is 6, while the sum is 8.

Adding to 21001001003 its reverse (30010010012), we get a palindrome (51011011015).

Subtracting 21001001003 from its reverse (30010010012), we obtain a palindrome (9009009009).

The spelling of 21001001003 in words is "twenty-one billion, one million, one thousand, three".