20565720 has 96 divisors (see below), whose sum is σ = 76396320. Its totient is φ = 4700160.

The previous prime is 20565719. The next prime is 20565731. The reversal of 20565720 is 2756502.

20565720 is a `hidden beast` number, since 2 + 0 + 5 + 657 + 2 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1561 + ... + 6600.

It is an arithmetic number, because the mean of its divisors is an integer number (795795).

Almost surely, 2^20565720 is an apocalyptic number.

20565720 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 20565720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38198160).

20565720 is an abundant number, since it is smaller than the sum of its proper divisors (55830600).

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

20565720 is a wasteful number, since it uses less digits than its factorization.

20565720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8185 (or 8178 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 20565720 is about 4534.9443215987. The cubic root of 20565720 is about 273.9773366447.

It can be divided in two parts, 2056 and 5720, that added together give a 5-th power (7776 = 6⁵).

The spelling of 20565720 in words is "twenty million, five hundred sixty-five thousand, seven hundred twenty".