21204434244242 has 8 divisors (see below), whose sum is σ = 33677630858556. Its totient is φ = 9978557291392.

The previous prime is 21204434244241. The next prime is 21204434244263. The reversal of 21204434244242 is 24244243440212.

It can be written as a sum of positive squares in 2 ways, for example, as 21068751785041 + 135682459201 = 4590071^2 + 368351^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21204434244196 and 21204434244205.

It is not an unprimeable number, because it can be changed into a prime (21204434244241) 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, 311829915323 + ... + 311829915390.

Almost surely, 2^{21204434244242} is an apocalyptic number.

21204434244242 is a deficient number, since it is larger than the sum of its proper divisors (12473196614314).

21204434244242 is a wasteful number, since it uses less digits than its factorization.

21204434244242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 623659830732.

The product of its (nonzero) digits is 393216, while the sum is 38.

Adding to 21204434244242 its reverse (24244243440212), we get a palindrome (45448677684454).

The spelling of 21204434244242 in words is "twenty-one trillion, two hundred four billion, four hundred thirty-four million, two hundred forty-four thousand, two hundred forty-two".