20566320 has 80 divisors (see below), whose sum is σ = 64757760. Its totient is φ = 5398272.

The previous prime is 20566267. The next prime is 20566331. The reversal of 20566320 is 2366502.

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

It is a Harshad number since it is a multiple of its sum of digits (24).

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 15 ways as a sum of consecutive naturals, for example, 15441 + ... + 16719.

It is an arithmetic number, because the mean of its divisors is an integer number (809472).

Almost surely, 2^20566320 is an apocalyptic number.

20566320 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 20566320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32378880).

20566320 is an abundant number, since it is smaller than the sum of its proper divisors (44191440).

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

20566320 is a wasteful number, since it uses less digits than its factorization.

20566320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1362 (or 1356 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 20566320 is about 4535.0104740783. The cubic root of 20566320 is about 273.9800010267.

The spelling of 20566320 in words is "twenty million, five hundred sixty-six thousand, three hundred twenty".