21085284799 has 16 divisors (see below), whose sum is σ = 22548556800. Its totient is φ = 19667989440.

The previous prime is 21085284793. The next prime is 21085284851. The reversal of 21085284799 is 99748258012.

It is a cyclic number.

It is not a de Polignac number, because 21085284799 - 2⁹ = 21085284287 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21085284793) 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, 3398302 + ... + 3404500.

It is an arithmetic number, because the mean of its divisors is an integer number (1409284800).

Almost surely, 2^21085284799 is an apocalyptic number.

21085284799 is a deficient number, since it is larger than the sum of its proper divisors (1463272001).

21085284799 is a wasteful number, since it uses less digits than its factorization.

21085284799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9870.

The product of its (nonzero) digits is 2903040, while the sum is 55.

The spelling of 21085284799 in words is "twenty-one billion, eighty-five million, two hundred eighty-four thousand, seven hundred ninety-nine".