21003132221 has 4 divisors (see below), whose sum is σ = 21102673344. Its totient is φ = 20903591100.

The previous prime is 21003132217. The next prime is 21003132229. The reversal of 21003132221 is 12223130012.

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 21003132221 - 2² = 21003132217 is a prime.

It is a super-2 number, since 2×21003132221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21003132221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003132229) 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, 49770245 + ... + 49770666.

It is an arithmetic number, because the mean of its divisors is an integer number (5275668336).

Almost surely, 2^21003132221 is an apocalyptic number.

It is an amenable number.

21003132221 is a deficient number, since it is larger than the sum of its proper divisors (99541123).

21003132221 is an equidigital number, since it uses as much as digits as its factorization.

21003132221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99541122.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21003132221 its reverse (12223130012), we get a palindrome (33226262233).

The spelling of 21003132221 in words is "twenty-one billion, three million, one hundred thirty-two thousand, two hundred twenty-one".