20400424 has 16 divisors (see below), whose sum is σ = 41728320. Its totient is φ = 9272880.

The previous prime is 20400421. The next prime is 20400437. The reversal of 20400424 is 42400402.

It is a junction number, because it is equal to n+sod(n) for n = 20400398 and 20400407.

It is not an unprimeable number, because it can be changed into a prime (20400421) 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 3 ways as a sum of consecutive naturals, for example, 115824 + ... + 115999.

It is an arithmetic number, because the mean of its divisors is an integer number (2608020).

Almost surely, 2^20400424 is an apocalyptic number.

It is an amenable number.

20400424 is an abundant number, since it is smaller than the sum of its proper divisors (21327896).

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

20400424 is a wasteful number, since it uses less digits than its factorization.

20400424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231840 (or 231836 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 16.

The square root of 20400424 is about 4516.6828535995. The cubic root of 20400424 is about 273.2413346278.

Adding to 20400424 its reverse (42400402), we get a palindrome (62800826).

The spelling of 20400424 in words is "twenty million, four hundred thousand, four hundred twenty-four".