20431424 has 42 divisors (see below), whose sum is σ = 43925490. Its totient is φ = 9424896.

The previous prime is 20431423. The next prime is 20431427. The reversal of 20431424 is 42413402.

It can be written as a sum of positive squares in 3 ways, for example, as 1024 + 20430400 = 32^2 + 4520^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20431396 and 20431405.

It is not an unprimeable number, because it can be changed into a prime (20431421) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9872 + ... + 11760.

It is an arithmetic number, because the mean of its divisors is an integer number (1045845).

Almost surely, 2^20431424 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20431424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21962745).

20431424 is an abundant number, since it is smaller than the sum of its proper divisors (23494066).

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

20431424 is a wasteful number, since it uses less digits than its factorization.

20431424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1927 (or 1904 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 20431424 is about 4520.1132729170. The cubic root of 20431424 is about 273.3796682637.

Adding to 20431424 its reverse (42413402), we get a palindrome (62844826).

The spelling of 20431424 in words is "twenty million, four hundred thirty-one thousand, four hundred twenty-four".