21545523999 has 12 divisors (see below), whose sum is σ = 32474413296. Its totient is φ = 13739174592.

The previous prime is 21545523949. The next prime is 21545524001. The reversal of 21545523999 is 99932554512.

21545523999 is a `hidden beast` number, since 2 + 1 + 54 + 552 + 39 + 9 + 9 = 666.

It is not a de Polignac number, because 21545523999 - 2¹⁶ = 21545458463 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21545523949) 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 11 ways as a sum of consecutive naturals, for example, 52042122 + ... + 52042535.

It is an arithmetic number, because the mean of its divisors is an integer number (2706201108).

Almost surely, 2^21545523999 is an apocalyptic number.

21545523999 is a deficient number, since it is larger than the sum of its proper divisors (10928889297).

21545523999 is a wasteful number, since it uses less digits than its factorization.

21545523999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104084686 (or 104084683 counting only the distinct ones).

The product of its digits is 4374000, while the sum is 54.

The spelling of 21545523999 in words is "twenty-one billion, five hundred forty-five million, five hundred twenty-three thousand, nine hundred ninety-nine".