21221321441 has 4 divisors (see below), whose sum is σ = 21427353792. Its totient is φ = 21015289092.

The previous prime is 21221321431. The next prime is 21221321453. The reversal of 21221321441 is 14412312212.

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 21221321441 - 2⁶ = 21221321377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221321411) 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, 103016021 + ... + 103016226.

It is an arithmetic number, because the mean of its divisors is an integer number (5356838448).

Almost surely, 2^21221321441 is an apocalyptic number.

It is an amenable number.

21221321441 is a deficient number, since it is larger than the sum of its proper divisors (206032351).

21221321441 is a wasteful number, since it uses less digits than its factorization.

21221321441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206032350.

The product of its digits is 768, while the sum is 23.

Adding to 21221321441 its reverse (14412312212), we get a palindrome (35633633653).

The spelling of 21221321441 in words is "twenty-one billion, two hundred twenty-one million, three hundred twenty-one thousand, four hundred forty-one".