100028720 has 80 divisors (see below), whose sum is σ = 255439008. Its totient is φ = 36126720.

The previous prime is 100028713. The next prime is 100028729. The reversal of 100028720 is 27820001.

It is a tau number, because it is divible by the number of its divisors (80).

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 = 100028692 and 100028701.

It is not an unprimeable number, because it can be changed into a prime (100028729) 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 15 ways as a sum of consecutive naturals, for example, 173072 + ... + 173648.

Almost surely, 2^100028720 is an apocalyptic number.

100028720 is a gapful number since it is divisible by the number (10) 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 100028720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127719504).

100028720 is an abundant number, since it is smaller than the sum of its proper divisors (155410288).

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

100028720 is a wasteful number, since it uses less digits than its factorization.

100028720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 798 (or 792 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 100028720 is about 10001.4358969100. The cubic root of 100028720 is about 464.2033145851.

Adding to 100028720 its reverse (27820001), we get a palindrome (127848721).

The spelling of 100028720 in words is "one hundred million, twenty-eight thousand, seven hundred twenty".