20288940 has 144 divisors (see below), whose sum is σ = 67721472. Its totient is φ = 4523904.

The previous prime is 20288929. The next prime is 20288969. The reversal of 20288940 is 4988202.

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 47 ways as a sum of consecutive naturals, for example, 196929 + ... + 197031.

It is an arithmetic number, because the mean of its divisors is an integer number (470288).

Almost surely, 2^20288940 is an apocalyptic number.

20288940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20288940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33860736).

20288940 is an abundant number, since it is smaller than the sum of its proper divisors (47432532).

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

20288940 is a wasteful number, since it uses less digits than its factorization.

20288940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196 (or 187 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 20288940 is about 4504.3245886592. The cubic root of 20288940 is about 272.7426898355.

The spelling of 20288940 in words is "twenty million, two hundred eighty-eight thousand, nine hundred forty".