21204221042 has 16 divisors (see below), whose sum is σ = 33493711680. Its totient is φ = 10048108752.

The previous prime is 21204221029. The next prime is 21204221047. The reversal of 21204221042 is 24012240212.

It is not an unprimeable number, because it can be changed into a prime (21204221047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2109488 + ... + 2119515.

It is an arithmetic number, because the mean of its divisors is an integer number (2093356980).

Almost surely, 2^21204221042 is an apocalyptic number.

21204221042 is a deficient number, since it is larger than the sum of its proper divisors (12289490638).

21204221042 is a wasteful number, since it uses less digits than its factorization.

21204221042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4229137.

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21204221042 its reverse (24012240212), we get a palindrome (45216461254).

The spelling of 21204221042 in words is "twenty-one billion, two hundred four million, two hundred twenty-one thousand, forty-two".