21564010011 has 16 divisors (see below), whose sum is σ = 29047127040. Its totient is φ = 14228807040.

The previous prime is 21564010001. The next prime is 21564010049. The reversal of 21564010011 is 11001046512.

It is not a de Polignac number, because 21564010011 - 2¹³ = 21564001819 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21564010011.

It is not an unprimeable number, because it can be changed into a prime (21564010001) 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, 199506 + ... + 287976.

It is an arithmetic number, because the mean of its divisors is an integer number (1815445440).

Almost surely, 2^21564010011 is an apocalyptic number.

21564010011 is a deficient number, since it is larger than the sum of its proper divisors (7483117029).

21564010011 is a wasteful number, since it uses less digits than its factorization.

21564010011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89306.

The product of its (nonzero) digits is 240, while the sum is 21.

Adding to 21564010011 its reverse (11001046512), we get a palindrome (32565056523).

The spelling of 21564010011 in words is "twenty-one billion, five hundred sixty-four million, ten thousand, eleven".