20210689 has 2 divisors, whose sum is σ = 20210690. Its totient is φ = 20210688.

The previous prime is 20210683. The next prime is 20210717. The reversal of 20210689 is 98601202.

It is a happy number.

It is an a-pointer prime, because the next prime (20210717) can be obtained adding 20210689 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19210689 + 1000000 = 4383^2 + 1000^2 .

It is a cyclic number.

It is not a de Polignac number, because 20210689 - 2⁵ = 20210657 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20210683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105344 + 10105345.

It is an arithmetic number, because the mean of its divisors is an integer number (10105345).

Almost surely, 2^20210689 is an apocalyptic number.

It is an amenable number.

20210689 is a deficient number, since it is larger than the sum of its proper divisors (1).

20210689 is an equidigital number, since it uses as much as digits as its factorization.

20210689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 20210689 is about 4495.6299892229. The cubic root of 20210689 is about 272.3915973166.

The spelling of 20210689 in words is "twenty million, two hundred ten thousand, six hundred eighty-nine".