21545208821835 has 64 divisors (see below), whose sum is σ = 40321622707200. Its totient is φ = 10893911745024.

The previous prime is 21545208821809. The next prime is 21545208821837. The reversal of 21545208821835 is 53812880254512.

21545208821835 is a `hidden beast` number, since 2 + 1 + 5 + 4 + 520 + 8 + 82 + 1 + 8 + 35 = 666.

It is not a de Polignac number, because 21545208821835 - 2¹² = 21545208817739 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21545208821837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 30352125 + ... + 31053854.

It is an arithmetic number, because the mean of its divisors is an integer number (630025354800).

Almost surely, 2^{21545208821835} is an apocalyptic number.

21545208821835 is a deficient number, since it is larger than the sum of its proper divisors (18776413885365).

21545208821835 is a wasteful number, since it uses less digits than its factorization.

21545208821835 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61406129 (or 61406123 counting only the distinct ones).

The product of its (nonzero) digits is 6144000, while the sum is 54.

The spelling of 21545208821835 in words is "twenty-one trillion, five hundred forty-five billion, two hundred eight million, eight hundred twenty-one thousand, eight hundred thirty-five".