20866320 has 120 divisors (see below), whose sum is σ = 71214936. Its totient is φ = 5474304.

The previous prime is 20866319. The next prime is 20866337. The reversal of 20866320 is 2366802.

20866320 is a `hidden beast` number, since 20 + 8 + 6 + 632 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3825936 + 17040384 = 1956^2 + 4128^2 .

It is a tau number, because it is divible by the number of its divisors (120).

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 23 ways as a sum of consecutive naturals, for example, 52362 + ... + 52758.

Almost surely, 2^20866320 is an apocalyptic number.

20866320 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 20866320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35607468).

20866320 is an abundant number, since it is smaller than the sum of its proper divisors (50348616).

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

20866320 is a wasteful number, since it uses less digits than its factorization.

20866320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489 (or 480 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 20866320 is about 4567.9667249226. The cubic root of 20866320 is about 275.3057535915.

The spelling of 20866320 in words is "twenty million, eight hundred sixty-six thousand, three hundred twenty".