21220320442 has 8 divisors (see below), whose sum is σ = 32044108500. Its totient is φ = 10538950944.

The previous prime is 21220320383. The next prime is 21220320461. The reversal of 21220320442 is 24402302212.

It can be written as a sum of positive squares in 2 ways, for example, as 18217170841 + 3003149601 = 134971^2 + 54801^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21220320442² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

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, 35604267 + ... + 35604862.

Almost surely, 2^21220320442 is an apocalyptic number.

21220320442 is a deficient number, since it is larger than the sum of its proper divisors (10823788058).

21220320442 is a wasteful number, since it uses less digits than its factorization.

21220320442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71209280.

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21220320442 its reverse (24402302212), we get a palindrome (45622622654).

The spelling of 21220320442 in words is "twenty-one billion, two hundred twenty million, three hundred twenty thousand, four hundred forty-two".