21085284800 has 42 divisors (see below), whose sum is σ = 51882982848. Its totient is φ = 8434113280.

The previous prime is 21085284793. The next prime is 21085284851. The reversal of 21085284800 is 848258012.

It is a super-2 number, since 2×21085284800² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 6587552 + ... + 6590751.

Almost surely, 2^21085284800 is an apocalyptic number.

21085284800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21085284800 is an abundant number, since it is smaller than the sum of its proper divisors (30797698048).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21085284800 is a wasteful number, since it uses less digits than its factorization.

21085284800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13178325 (or 13178310 counting only the distinct ones).

The product of its (nonzero) digits is 40960, while the sum is 38.

The spelling of 21085284800 in words is "twenty-one billion, eighty-five million, two hundred eighty-four thousand, eight hundred".