21220440331 has 4 divisors (see below), whose sum is σ = 21568316464. Its totient is φ = 20872564200.

The previous prime is 21220440317. The next prime is 21220440433. The reversal of 21220440331 is 13304402212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21220440331 - 2⁷ = 21220440203 is a prime.

It is a super-2 number, since 2×21220440331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220440931) 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, 173937975 + ... + 173938096.

It is an arithmetic number, because the mean of its divisors is an integer number (5392079116).

Almost surely, 2^21220440331 is an apocalyptic number.

21220440331 is a deficient number, since it is larger than the sum of its proper divisors (347876133).

21220440331 is an equidigital number, since it uses as much as digits as its factorization.

21220440331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347876132.

The product of its (nonzero) digits is 1152, while the sum is 22.

Adding to 21220440331 its reverse (13304402212), we get a palindrome (34524842543).

The spelling of 21220440331 in words is "twenty-one billion, two hundred twenty million, four hundred forty thousand, three hundred thirty-one".