21101048644 has 81 divisors (see below), whose sum is σ = 41369729751. Its totient is φ = 9412977600.

The previous prime is 21101048627. The next prime is 21101048693. The reversal of 21101048644 is 44684010112.

The square root of 21101048644 is 145262.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 87647044 + 21013401600 = 9362^2 + 144960^2 .

It is a Duffinian number.

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 in 26 ways as a sum of consecutive naturals, for example, 139741969 + ... + 139742119.

Almost surely, 2^21101048644 is an apocalyptic number.

21101048644 is the 145262-nd square number.

It is an amenable number.

21101048644 is a deficient number, since it is larger than the sum of its proper divisors (20268681107).

21101048644 is a wasteful number, since it uses less digits than its factorization.

21101048644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 31.

Adding to 21101048644 its reverse (44684010112), we get a palindrome (65785058756).

The spelling of 21101048644 in words is "twenty-one billion, one hundred one million, forty-eight thousand, six hundred forty-four".