20008861 has 4 divisors (see below), whose sum is σ = 20496924. Its totient is φ = 19520800.

The previous prime is 20008829. The next prime is 20008871. The reversal of 20008861 is 16880002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6095961 + 13912900 = 2469^2 + 3730^2 .

It is a cyclic number.

It is not a de Polignac number, because 20008861 - 2⁵ = 20008829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20008801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 243970 + ... + 244051.

It is an arithmetic number, because the mean of its divisors is an integer number (5124231).

Almost surely, 2^20008861 is an apocalyptic number.

It is an amenable number.

20008861 is a deficient number, since it is larger than the sum of its proper divisors (488063).

20008861 is an equidigital number, since it uses as much as digits as its factorization.

20008861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488062.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 20008861 is about 4473.1265352100. The cubic root of 20008861 is about 271.4818431649.

Adding to 20008861 its reverse (16880002), we get a palindrome (36888863).

The spelling of 20008861 in words is "twenty million, eight thousand, eight hundred sixty-one".