20985686400 has 768 divisors, whose sum is σ = 82566144000. Its totient is φ = 4586250240.

The previous prime is 20985686383. The next prime is 20985686413. The reversal of 20985686400 is 468658902.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 20985686400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 265641561 + ... + 265641639.

It is an arithmetic number, because the mean of its divisors is an integer number (107508000).

Almost surely, 2^20985686400 is an apocalyptic number.

20985686400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20985686400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41283072000).

20985686400 is an abundant number, since it is smaller than the sum of its proper divisors (61580457600).

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

20985686400 is a wasteful number, since it uses less digits than its factorization.

20985686400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239 (or 222 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 48.

The spelling of 20985686400 in words is "twenty billion, nine hundred eighty-five million, six hundred eighty-six thousand, four hundred".