20028645 has 96 divisors (see below), whose sum is σ = 43959552. Its totient is φ = 8211456.

The previous prime is 20028637. The next prime is 20028661. The reversal of 20028645 is 54682002.

It is not a de Polignac number, because 20028645 - 2³ = 20028637 is a prime.

It is a super-4 number, since 4×20028645⁴ (a number of 30 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 274329 + ... + 274401.

It is an arithmetic number, because the mean of its divisors is an integer number (457912).

Almost surely, 2^20028645 is an apocalyptic number.

It is an amenable number.

20028645 is an abundant number, since it is smaller than the sum of its proper divisors (23930907).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20028645 is a wasteful number, since it uses less digits than its factorization.

20028645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171 (or 168 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 20028645 is about 4475.3374174469. The cubic root of 20028645 is about 271.5712906609.

The spelling of 20028645 in words is "twenty million, twenty-eight thousand, six hundred forty-five".