20288840 has 64 divisors (see below), whose sum is σ = 53645760. Its totient is φ = 6808320.

The previous prime is 20288797. The next prime is 20288843. The reversal of 20288840 is 4888202.

It is a super-3 number, since 3×20288840³ (a number of 23 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 20288797 and 20288806.

It is not an unprimeable number, because it can be changed into a prime (20288843) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 3947 + ... + 7493.

It is an arithmetic number, because the mean of its divisors is an integer number (838215).

Almost surely, 2^20288840 is an apocalyptic number.

20288840 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 20288840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26822880).

20288840 is an abundant number, since it is smaller than the sum of its proper divisors (33356920).

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

20288840 is a wasteful number, since it uses less digits than its factorization.

20288840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3582 (or 3578 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 32.

The square root of 20288840 is about 4504.3134882022. The cubic root of 20288840 is about 272.7422417373.

The spelling of 20288840 in words is "twenty million, two hundred eighty-eight thousand, eight hundred forty".