21312444242 has 4 divisors (see below), whose sum is σ = 31968666366. Its totient is φ = 10656222120.

The previous prime is 21312444227. The next prime is 21312444289. The reversal of 21312444242 is 24244421312.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 19742779081 + 1569665161 = 140509^2 + 39619^2 .

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 as a sum of consecutive naturals, namely, 5328111059 + ... + 5328111062.

Almost surely, 2^21312444242 is an apocalyptic number.

21312444242 is a deficient number, since it is larger than the sum of its proper divisors (10656222124).

21312444242 is a wasteful number, since it uses less digits than its factorization.

21312444242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10656222123.

The product of its digits is 12288, while the sum is 29.

Adding to 21312444242 its reverse (24244421312), we get a palindrome (45556865554).

The spelling of 21312444242 in words is "twenty-one billion, three hundred twelve million, four hundred forty-four thousand, two hundred forty-two".