21305449635 has 16 divisors (see below), whose sum is σ = 34215449760. Its totient is φ = 11320663040.

The previous prime is 21305449621. The next prime is 21305449637. The reversal of 21305449635 is 53694450312.

It is not a de Polignac number, because 21305449635 - 2⁵ = 21305449603 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21305449637) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2636046 + ... + 2644115.

It is an arithmetic number, because the mean of its divisors is an integer number (2138465610).

Almost surely, 2^21305449635 is an apocalyptic number.

21305449635 is a deficient number, since it is larger than the sum of its proper divisors (12910000125).

21305449635 is a wasteful number, since it uses less digits than its factorization.

21305449635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5280438.

The product of its (nonzero) digits is 388800, while the sum is 42.

Adding to 21305449635 its reverse (53694450312), we get a palindrome (74999899947).

The spelling of 21305449635 in words is "twenty-one billion, three hundred five million, four hundred forty-nine thousand, six hundred thirty-five".