21509885443 has 16 divisors (see below), whose sum is σ = 23108379840. Its totient is φ = 19948723200.

The previous prime is 21509885429. The next prime is 21509885483. The reversal of 21509885443 is 34458890512.

It is a cyclic number.

It is not a de Polignac number, because 21509885443 - 2¹³ = 21509877251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21509885413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3039313 + ... + 3046381.

It is an arithmetic number, because the mean of its divisors is an integer number (1444273740).

Almost surely, 2^21509885443 is an apocalyptic number.

21509885443 is a deficient number, since it is larger than the sum of its proper divisors (1598494397).

21509885443 is a wasteful number, since it uses less digits than its factorization.

21509885443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9678.

The product of its (nonzero) digits is 1382400, while the sum is 49.

The spelling of 21509885443 in words is "twenty-one billion, five hundred nine million, eight hundred eighty-five thousand, four hundred forty-three".