21001003221 has 16 divisors (see below), whose sum is σ = 32154647040. Its totient is φ = 12057991920.

The previous prime is 21001003211. The next prime is 21001003249. The reversal of 21001003221 is 12230010012.

It is not a de Polignac number, because 21001003221 - 2⁹ = 21001002709 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21001003197 and 21001003206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001003211) 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 15 ways as a sum of consecutive naturals, for example, 16746585 + ... + 16747838.

It is an arithmetic number, because the mean of its divisors is an integer number (2009665440).

Almost surely, 2^21001003221 is an apocalyptic number.

It is an amenable number.

21001003221 is a deficient number, since it is larger than the sum of its proper divisors (11153643819).

21001003221 is a wasteful number, since it uses less digits than its factorization.

21001003221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33494456.

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21001003221 its reverse (12230010012), we get a palindrome (33231013233).

The spelling of 21001003221 in words is "twenty-one billion, one million, three thousand, two hundred twenty-one".