20424240 has 120 divisors (see below), whose sum is σ = 72249840. Its totient is φ = 5156352.

The previous prime is 20424199. The next prime is 20424247. The reversal of 20424240 is 4242402.

20424240 is a `hidden beast` number, since 2 + 0 + 424 + 240 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is not an unprimeable number, because it can be changed into a prime (20424247) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12934 + ... + 14426.

It is an arithmetic number, because the mean of its divisors is an integer number (602082).

Almost surely, 2^20424240 is an apocalyptic number.

20424240 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 20424240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36124920).

20424240 is an abundant number, since it is smaller than the sum of its proper divisors (51825600).

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

20424240 is a wasteful number, since it uses less digits than its factorization.

20424240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1531 (or 1522 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 18.

The square root of 20424240 is about 4519.3185326994. The cubic root of 20424240 is about 273.3476230219.

Adding to 20424240 its reverse (4242402), we get a palindrome (24666642).

The spelling of 20424240 in words is "twenty million, four hundred twenty-four thousand, two hundred forty".