20404020 has 192 divisors, whose sum is σ = 72930816. Its totient is φ = 4147200.

The previous prime is 20404009. The next prime is 20404039. The reversal of 20404020 is 2040402.

20404020 = T₂₅₉ + T₂₆₀ + ... + T₅₁₈.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 20403987 and 20404005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 201970 + ... + 202070.

It is an arithmetic number, because the mean of its divisors is an integer number (379848).

Almost surely, 2^20404020 is an apocalyptic number.

20404020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20404020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36465408).

20404020 is an abundant number, since it is smaller than the sum of its proper divisors (52526796).

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

20404020 is a wasteful number, since it uses less digits than its factorization.

20404020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170 (or 168 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 12.

The square root of 20404020 is about 4517.0809158128. The cubic root of 20404020 is about 273.2573885116.

Adding to 20404020 its reverse (2040402), we get a palindrome (22444422).

The spelling of 20404020 in words is "twenty million, four hundred four thousand, twenty".