20581568 has 42 divisors (see below), whose sum is σ = 47516796. Its totient is φ = 8819328.

The previous prime is 20581559. The next prime is 20581571. The reversal of 20581568 is 86518502.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 146 + ... + 6417.

Almost surely, 2^20581568 is an apocalyptic number.

20581568 is a gapful number since it is divisible by the number (28) 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 20581568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23758398).

20581568 is an abundant number, since it is smaller than the sum of its proper divisors (26935228).

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

20581568 is an equidigital number, since it uses as much as digits as its factorization.

20581568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6589 (or 6572 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 35.

The square root of 20581568 is about 4536.6913053458. The cubic root of 20581568 is about 274.0476944698.

The spelling of 20581568 in words is "twenty million, five hundred eighty-one thousand, five hundred sixty-eight".