21545541504205 has 16 divisors (see below), whose sum is σ = 27382000639680. Its totient is φ = 16218679986432.

The previous prime is 21545541504203. The next prime is 21545541504233. The reversal of 21545541504205 is 50240514554512.

It is a cyclic number.

It is not a de Polignac number, because 21545541504205 - 2¹ = 21545541504203 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21545541504203) 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, 29681319 + ... + 30398548.

It is an arithmetic number, because the mean of its divisors is an integer number (1711375039980).

Almost surely, 2^{21545541504205} is an apocalyptic number.

It is an amenable number.

21545541504205 is a deficient number, since it is larger than the sum of its proper divisors (5836459135475).

21545541504205 is a wasteful number, since it uses less digits than its factorization.

21545541504205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60084108.

The product of its (nonzero) digits is 800000, while the sum is 43.

The spelling of 21545541504205 in words is "twenty-one trillion, five hundred forty-five billion, five hundred forty-one million, five hundred four thousand, two hundred five".