21685847040 has 704 divisors, whose sum is σ = 90623473920. Its totient is φ = 4848353280.

The previous prime is 21685847039. The next prime is 21685847069. The reversal of 21685847040 is 4074858612.

21685847040 is a `hidden beast` number, since 2 + 1 + 68 + 584 + 7 + 0 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (704).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 19767772 + ... + 19768868.

Almost surely, 2^21685847040 is an apocalyptic number.

21685847040 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 21685847040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45311736960).

21685847040 is an abundant number, since it is smaller than the sum of its proper divisors (68937626880).

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

21685847040 is a wasteful number, since it uses less digits than its factorization.

21685847040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1155 (or 1131 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 45.

The spelling of 21685847040 in words is "twenty-one billion, six hundred eighty-five million, eight hundred forty-seven thousand, forty".