21010003221 has 4 divisors (see below), whose sum is σ = 28013337632. Its totient is φ = 14006668812.

The previous prime is 21010003219. The next prime is 21010003229. The reversal of 21010003221 is 12230001012.

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 not a de Polignac number, because 21010003221 - 2¹ = 21010003219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010003197 and 21010003206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010003229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3501667201 + ... + 3501667206.

It is an arithmetic number, because the mean of its divisors is an integer number (7003334408).

Almost surely, 2^21010003221 is an apocalyptic number.

It is an amenable number.

21010003221 is a deficient number, since it is larger than the sum of its proper divisors (7003334411).

21010003221 is an equidigital number, since it uses as much as digits as its factorization.

21010003221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7003334410.

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

Adding to 21010003221 its reverse (12230001012), we get a palindrome (33240004233).

The spelling of 21010003221 in words is "twenty-one billion, ten million, three thousand, two hundred twenty-one".