20806889 has 4 divisors (see below), whose sum is σ = 20816256. Its totient is φ = 20797524.

The previous prime is 20806871. The next prime is 20806897. The reversal of 20806889 is 98860802.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20806889 - 2⁸ = 20806633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20806829) 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, 752 + ... + 6494.

It is an arithmetic number, because the mean of its divisors is an integer number (5204064).

Almost surely, 2^20806889 is an apocalyptic number.

It is an amenable number.

20806889 is a deficient number, since it is larger than the sum of its proper divisors (9367).

20806889 is an equidigital number, since it uses as much as digits as its factorization.

20806889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9366.

The product of its (nonzero) digits is 55296, while the sum is 41.

The square root of 20806889 is about 4561.4568944582. The cubic root of 20806889 is about 275.0441317604.

The spelling of 20806889 in words is "twenty million, eight hundred six thousand, eight hundred eighty-nine".