20387789 has 2 divisors, whose sum is σ = 20387790. Its totient is φ = 20387788.

The previous prime is 20387771. The next prime is 20387791. The reversal of 20387789 is 98778302.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18774889 + 1612900 = 4333^2 + 1270^2 .

It is a cyclic number.

It is not a de Polignac number, because 20387789 - 2²⁰ = 19339213 is a prime.

Together with 20387791, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20387089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10193894 + 10193895.

It is an arithmetic number, because the mean of its divisors is an integer number (10193895).

Almost surely, 2^20387789 is an apocalyptic number.

It is an amenable number.

20387789 is a deficient number, since it is larger than the sum of its proper divisors (1).

20387789 is an equidigital number, since it uses as much as digits as its factorization.

20387789 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 169344, while the sum is 44.

The square root of 20387789 is about 4515.2839334864. The cubic root of 20387789 is about 273.1849123159.

The spelling of 20387789 in words is "twenty million, three hundred eighty-seven thousand, seven hundred eighty-nine".