20404820 has 24 divisors (see below), whose sum is σ = 44233728. Its totient is φ = 7898400.

The previous prime is 20404817. The next prime is 20404837. The reversal of 20404820 is 2840402.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 20404792 and 20404801.

It is a congruent number.

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, 15836 + ... + 17075.

It is an arithmetic number, because the mean of its divisors is an integer number (1843072).

Almost surely, 2^20404820 is an apocalyptic number.

20404820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20404820 is an abundant number, since it is smaller than the sum of its proper divisors (23828908).

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

20404820 is a wasteful number, since it uses less digits than its factorization.

20404820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32951 (or 32949 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

The square root of 20404820 is about 4517.1694677087. The cubic root of 20404820 is about 273.2609597532.

The spelling of 20404820 in words is "twenty million, four hundred four thousand, eight hundred twenty".