20428900 has 72 divisors (see below), whose sum is σ = 47950056. Its totient is φ = 7526400.

The previous prime is 20428843. The next prime is 20428909. The reversal of 20428900 is 982402.

It can be written as a sum of positive squares in 12 ways, for example, as 2637376 + 17791524 = 1624^2 + 4218^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20428909) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 103602 + ... + 103798.

It is an arithmetic number, because the mean of its divisors is an integer number (665973).

Almost surely, 2^20428900 is an apocalyptic number.

20428900 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 20428900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23975028).

20428900 is an abundant number, since it is smaller than the sum of its proper divisors (27521156).

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

20428900 is a wasteful number, since it uses less digits than its factorization.

20428900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289 (or 282 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 20428900 is about 4519.8340677507. The cubic root of 20428900 is about 273.3684104630.

The spelling of 20428900 in words is "twenty million, four hundred twenty-eight thousand, nine hundred".