21031030221 has 4 divisors (see below), whose sum is σ = 28041373632. Its totient is φ = 14020686812.

The previous prime is 21031030217. The next prime is 21031030243. The reversal of 21031030221 is 12203013012.

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 21031030221 - 2² = 21031030217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21031030221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031030211) 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, 3505171701 + ... + 3505171706.

It is an arithmetic number, because the mean of its divisors is an integer number (7010343408).

Almost surely, 2^21031030221 is an apocalyptic number.

It is an amenable number.

21031030221 is a deficient number, since it is larger than the sum of its proper divisors (7010343411).

21031030221 is an equidigital number, since it uses as much as digits as its factorization.

21031030221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7010343410.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21031030221 its reverse (12203013012), we get a palindrome (33234043233).

The spelling of 21031030221 in words is "twenty-one billion, thirty-one million, thirty thousand, two hundred twenty-one".