20420420 has 24 divisors (see below), whose sum is σ = 43127448. Its totient is φ = 8121600.

The previous prime is 20420377. The next prime is 20420443. The reversal of 20420420 is 2402402.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2033476 + 18386944 = 1426^2 + 4288^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20420395 and 20420404.

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 7 ways as a sum of consecutive naturals, for example, 800 + ... + 6440.

It is an arithmetic number, because the mean of its divisors is an integer number (1796977).

Almost surely, 2^20420420 is an apocalyptic number.

20420420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20420420 is an abundant number, since it is smaller than the sum of its proper divisors (22707028).

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

20420420 is a wasteful number, since it uses less digits than its factorization.

20420420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5831 (or 5829 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 14.

The square root of 20420420 is about 4518.8958828457. The cubic root of 20420420 is about 273.3305803147.

Adding to 20420420 its reverse (2402402), we get a palindrome (22822822).

The spelling of 20420420 in words is "twenty million, four hundred twenty thousand, four hundred twenty".