20400800 has 72 divisors (see below), whose sum is σ = 56933856. Its totient is φ = 6992640.

The previous prime is 20400719. The next prime is 20400803. The reversal of 20400800 is 800402.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is not an unprimeable number, because it can be changed into a prime (20400803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3779 + ... + 7421.

It is an arithmetic number, because the mean of its divisors is an integer number (790748).

Almost surely, 2^20400800 is an apocalyptic number.

20400800 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 20400800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28466928).

20400800 is an abundant number, since it is smaller than the sum of its proper divisors (36533056).

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

20400800 is a wasteful number, since it uses less digits than its factorization.

20400800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3670 (or 3657 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 20400800 is about 4516.7244768748. The cubic root of 20400800 is about 273.2430133202.

The spelling of 20400800 in words is "twenty million, four hundred thousand, eight hundred".