20928489 has 8 divisors (see below), whose sum is σ = 28498560. Its totient is φ = 13655376.

The previous prime is 20928473. The next prime is 20928499. The reversal of 20928489 is 98482902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20928489 - 2⁴ = 20928473 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20928489.

It is not an unprimeable number, because it can be changed into a prime (20928419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74074 + ... + 74355.

It is an arithmetic number, because the mean of its divisors is an integer number (3562320).

Almost surely, 2^20928489 is an apocalyptic number.

It is an amenable number.

20928489 is a deficient number, since it is larger than the sum of its proper divisors (7570071).

20928489 is a wasteful number, since it uses less digits than its factorization.

20928489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148479.

The product of its (nonzero) digits is 82944, while the sum is 42.

The square root of 20928489 is about 4574.7665514210. The cubic root of 20928489 is about 275.5788973234.

The spelling of 20928489 in words is "twenty million, nine hundred twenty-eight thousand, four hundred eighty-nine".