20208240 has 240 divisors, whose sum is σ = 77995008. Its totient is φ = 4644864.

The previous prime is 20208217. The next prime is 20208241. The reversal of 20208240 is 4280202.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20208241) 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 47 ways as a sum of consecutive naturals, for example, 159057 + ... + 159183.

Almost surely, 2^20208240 is an apocalyptic number.

20208240 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 20208240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38997504).

20208240 is an abundant number, since it is smaller than the sum of its proper divisors (57786768).

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

20208240 is a wasteful number, since it uses less digits than its factorization.

20208240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176 (or 167 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 20208240 is about 4495.3576053524. The cubic root of 20208240 is about 272.3805946574.

Adding to 20208240 its reverse (4280202), we get a palindrome (24488442).

The spelling of 20208240 in words is "twenty million, two hundred eight thousand, two hundred forty".