21131224442 has 16 divisors (see below), whose sum is σ = 31855310592. Its totient is φ = 10512836640.

The previous prime is 21131224441. The next prime is 21131224459. The reversal of 21131224442 is 24442213112.

It is a super-2 number, since 2×21131224442² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21131224441) 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 7 ways as a sum of consecutive naturals, for example, 942017 + ... + 964187.

It is an arithmetic number, because the mean of its divisors is an integer number (1990956912).

Almost surely, 2^21131224442 is an apocalyptic number.

21131224442 is a deficient number, since it is larger than the sum of its proper divisors (10724086150).

21131224442 is a wasteful number, since it uses less digits than its factorization.

21131224442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24533.

The product of its digits is 3072, while the sum is 26.

Adding to 21131224442 its reverse (24442213112), we get a palindrome (45573437554).

The spelling of 21131224442 in words is "twenty-one billion, one hundred thirty-one million, two hundred twenty-four thousand, four hundred forty-two".