20389945 has 8 divisors (see below), whose sum is σ = 25755840. Its totient is φ = 15453360.

The previous prime is 20389927. The next prime is 20389951. The reversal of 20389945 is 54998302.

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 20389945 - 2⁵ = 20389913 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20389898 and 20389907.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 107221 + ... + 107410.

It is an arithmetic number, because the mean of its divisors is an integer number (3219480).

Almost surely, 2^20389945 is an apocalyptic number.

It is an amenable number.

20389945 is a deficient number, since it is larger than the sum of its proper divisors (5365895).

20389945 is a wasteful number, since it uses less digits than its factorization.

20389945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214655.

The product of its (nonzero) digits is 77760, while the sum is 40.

The square root of 20389945 is about 4515.5226718510. The cubic root of 20389945 is about 273.1945417058.

The spelling of 20389945 in words is "twenty million, three hundred eighty-nine thousand, nine hundred forty-five".