20420424 has 40 divisors (see below), whose sum is σ = 57197910. Its totient is φ = 6806592.

The previous prime is 20420377. The next prime is 20420443. The reversal of 20420424 is 42402402.

It can be written as a sum of positive squares in only one way, i.e., 20412324 + 8100 = 4518^2 + 90^2 .

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

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

It is a junction number, because it is equal to n+sod(n) for n = 20420397 and 20420406.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 15109 + ... + 16404.

Almost surely, 2^20420424 is an apocalyptic number.

20420424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20420424 is an abundant number, since it is smaller than the sum of its proper divisors (36777486).

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

20420424 is a wasteful number, since it uses less digits than its factorization.

20420424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31531 (or 31518 counting only the distinct ones).

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

The square root of 20420424 is about 4518.8963254317. The cubic root of 20420424 is about 273.3305981615.

Adding to 20420424 its reverse (42402402), we get a palindrome (62822826).

The spelling of 20420424 in words is "twenty million, four hundred twenty thousand, four hundred twenty-four".