21236013442 has 48 divisors (see below), whose sum is σ = 38535376320. Its totient is φ = 8596583136.

The previous prime is 21236013397. The next prime is 21236013443. The reversal of 21236013442 is 24431063212.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21236013442.

It is not an unprimeable number, because it can be changed into a prime (21236013443) 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 23 ways as a sum of consecutive naturals, for example, 1747684 + ... + 1759792.

It is an arithmetic number, because the mean of its divisors is an integer number (802820340).

Almost surely, 2^21236013442 is an apocalyptic number.

21236013442 is a deficient number, since it is larger than the sum of its proper divisors (17299362878).

21236013442 is a wasteful number, since it uses less digits than its factorization.

21236013442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12503 (or 12484 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 28.

Adding to 21236013442 its reverse (24431063212), we get a palindrome (45667076654).

The spelling of 21236013442 in words is "twenty-one billion, two hundred thirty-six million, thirteen thousand, four hundred forty-two".