21224545520645 has 8 divisors (see below), whose sum is σ = 26967657838104. Its totient is φ = 15980834274304.

The previous prime is 21224545520639. The next prime is 21224545520681. The reversal of 21224545520645 is 54602554542212.

It can be written as a sum of positive squares in 4 ways, for example, as 4517363417281 + 16707182103364 = 2125409^2 + 4087442^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21224545520645 - 2⁸ = 21224545520389 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21224545520645.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 124850267684 + ... + 124850267853.

It is an arithmetic number, because the mean of its divisors is an integer number (3370957229763).

Almost surely, 2^{21224545520645} is an apocalyptic number.

It is an amenable number.

21224545520645 is a deficient number, since it is larger than the sum of its proper divisors (5743112317459).

21224545520645 is a wasteful number, since it uses less digits than its factorization.

21224545520645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249700535559.

The product of its (nonzero) digits is 3840000, while the sum is 47.

The spelling of 21224545520645 in words is "twenty-one trillion, two hundred twenty-four billion, five hundred forty-five million, five hundred twenty thousand, six hundred forty-five".