20404420 has 24 divisors (see below), whose sum is σ = 45370584. Its totient is φ = 7681536.

The previous prime is 20404411. The next prime is 20404421. The reversal of 20404420 is 2440402.

It can be written as a sum of positive squares in 4 ways, for example, as 6625476 + 13778944 = 2574^2 + 3712^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20404394 and 20404403.

It is not an unprimeable number, because it can be changed into a prime (20404421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29667 + ... + 30346.

It is an arithmetic number, because the mean of its divisors is an integer number (1890441).

Almost surely, 2^20404420 is an apocalyptic number.

20404420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20404420 is an abundant number, since it is smaller than the sum of its proper divisors (24966164).

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

20404420 is a wasteful number, since it uses less digits than its factorization.

20404420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60039 (or 60037 counting only the distinct ones).

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

The square root of 20404420 is about 4517.1251919777. The cubic root of 20404420 is about 273.2591741441.

Adding to 20404420 its reverse (2440402), we get a palindrome (22844822).

The spelling of 20404420 in words is "twenty million, four hundred four thousand, four hundred twenty".