21786160 has 80 divisors (see below), whose sum is σ = 58210560. Its totient is φ = 7499520.

The previous prime is 21786133. The next prime is 21786173. The reversal of 21786160 is 6168712.

It is a tau number, because it is divible by the number of its divisors (80).

It is a zygodrome in base 3.

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 15 ways as a sum of consecutive naturals, for example, 16069 + ... + 17371.

It is an arithmetic number, because the mean of its divisors is an integer number (727632).

Almost surely, 2^21786160 is an apocalyptic number.

21786160 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 21786160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29105280).

21786160 is an abundant number, since it is smaller than the sum of its proper divisors (36424400).

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

21786160 is a wasteful number, since it uses less digits than its factorization.

21786160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1346 (or 1340 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21786160 is about 4667.5646755026. The cubic root of 21786160 is about 279.2931148660.

It can be divided in two parts, 2178 and 6160, that added together give a palindrome (8338).

The spelling of 21786160 in words is "twenty-one million, seven hundred eighty-six thousand, one hundred sixty".