21431130221 has 4 divisors (see below), whose sum is σ = 21433776672. Its totient is φ = 21428483772.

The previous prime is 21431130209. The next prime is 21431130241. The reversal of 21431130221 is 12203113412.

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 21431130221 - 2¹⁰ = 21431129197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21431130193 and 21431130202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431130241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1311041 + ... + 1327286.

It is an arithmetic number, because the mean of its divisors is an integer number (5358444168).

Almost surely, 2^21431130221 is an apocalyptic number.

It is an amenable number.

21431130221 is a deficient number, since it is larger than the sum of its proper divisors (2646451).

21431130221 is an equidigital number, since it uses as much as digits as its factorization.

21431130221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2646450.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 21431130221 its reverse (12203113412), we get a palindrome (33634243633).

The spelling of 21431130221 in words is "twenty-one billion, four hundred thirty-one million, one hundred thirty thousand, two hundred twenty-one".