20006581 has 8 divisors (see below), whose sum is σ = 22904640. Its totient is φ = 17118528.

The previous prime is 20006579. The next prime is 20006611. The reversal of 20006581 is 18560002.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20006581 - 2¹ = 20006579 is a prime.

It is a super-2 number, since 2×20006581² = 800526566619122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20006531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2445 + ... + 6781.

It is an arithmetic number, because the mean of its divisors is an integer number (2863080).

Almost surely, 2^20006581 is an apocalyptic number.

It is an amenable number.

20006581 is a deficient number, since it is larger than the sum of its proper divisors (2898059).

20006581 is an equidigital number, since it uses as much as digits as its factorization.

20006581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5003.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 20006581 is about 4472.8716726506. The cubic root of 20006581 is about 271.4715310318.

Adding to 20006581 its reverse (18560002), we get a palindrome (38566583).

The spelling of 20006581 in words is "twenty million, six thousand, five hundred eighty-one".