21085284852 has 96 divisors (see below), whose sum is σ = 56688441600. Its totient is φ = 6769526400.

The previous prime is 21085284851. The next prime is 21085284917. The reversal of 21085284852 is 25848258012.

21085284852 is a `hidden beast` number, since 210 + 85 + 284 + 85 + 2 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21085284798 and 21085284807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21085284851) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1310577 + ... + 1326567.

It is an arithmetic number, because the mean of its divisors is an integer number (590504600).

Almost surely, 2^21085284852 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21085284852, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28344220800).

21085284852 is an abundant number, since it is smaller than the sum of its proper divisors (35603156748).

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

21085284852 is a wasteful number, since it uses less digits than its factorization.

21085284852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16454 (or 16446 counting only the distinct ones).

The product of its (nonzero) digits is 409600, while the sum is 45.

The spelling of 21085284852 in words is "twenty-one billion, eighty-five million, two hundred eighty-four thousand, eight hundred fifty-two".