20288720 has 20 divisors (see below), whose sum is σ = 47171460. Its totient is φ = 8115456.

The previous prime is 20288717. The next prime is 20288731. The reversal of 20288720 is 2788202.

It can be written as a sum of positive squares in 2 ways, for example, as 7529536 + 12759184 = 2744^2 + 3572^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 126725 + ... + 126884.

It is an arithmetic number, because the mean of its divisors is an integer number (2358573).

Almost surely, 2^20288720 is an apocalyptic number.

20288720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20288720 is an abundant number, since it is smaller than the sum of its proper divisors (26882740).

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

20288720 is a wasteful number, since it uses less digits than its factorization.

20288720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253622 (or 253616 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 29.

The square root of 20288720 is about 4504.3001676176. The cubic root of 20288720 is about 272.7417040175.

The spelling of 20288720 in words is "twenty million, two hundred eighty-eight thousand, seven hundred twenty".