21115653424605 has 12 divisors (see below), whose sum is σ = 36600465936060. Its totient is φ = 11261681826432.

The previous prime is 21115653424603. The next prime is 21115653424633. The reversal of 21115653424605 is 50642435651112.

21115653424605 is a `hidden beast` number, since 2 + 1 + 1 + 1 + 5 + 6 + 5 + 34 + 2 + 4 + 605 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 10123583970564 + 10992069454041 = 3181758^2 + 3315429^2 .

It is not a de Polignac number, because 21115653424605 - 2¹ = 21115653424603 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 469236742769 = 21115653424605 / (2 + 1 + 1 + 1 + 5 + 6 + 5 + 3 + 4 + 2 + 4 + 6 + 0 + 5).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115653424603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 234618371340 + ... + 234618371429.

It is an arithmetic number, because the mean of its divisors is an integer number (3050038828005).

Almost surely, 2^{21115653424605} is an apocalyptic number.

It is an amenable number.

21115653424605 is a deficient number, since it is larger than the sum of its proper divisors (15484812511455).

21115653424605 is a wasteful number, since it uses less digits than its factorization.

21115653424605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 469236742780 (or 469236742777 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 45.

The spelling of 21115653424605 in words is "twenty-one trillion, one hundred fifteen billion, six hundred fifty-three million, four hundred twenty-four thousand, six hundred five".