21236563105 has 16 divisors (see below), whose sum is σ = 26215189200. Its totient is φ = 16503201792.

The previous prime is 21236563087. The next prime is 21236563109. The reversal of 21236563105 is 50136563212.

It can be written as a sum of positive squares in 8 ways, for example, as 1935296064 + 19301267041 = 43992^2 + 138929^2 .

It is a cyclic number.

It is not a de Polignac number, because 21236563105 - 2⁹ = 21236562593 is a prime.

It is a super-2 number, since 2×21236563105² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21236563109) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 21121 + ... + 207169.

It is an arithmetic number, because the mean of its divisors is an integer number (1638449325).

Almost surely, 2^21236563105 is an apocalyptic number.

It is an amenable number.

21236563105 is a deficient number, since it is larger than the sum of its proper divisors (4978626095).

21236563105 is a wasteful number, since it uses less digits than its factorization.

21236563105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186708.

The product of its (nonzero) digits is 32400, while the sum is 34.

The spelling of 21236563105 in words is "twenty-one billion, two hundred thirty-six million, five hundred sixty-three thousand, one hundred five".