100721872 has 60 divisors (see below), whose sum is σ = 215661420. Its totient is φ = 45359104.

The previous prime is 100721857. The next prime is 100721879. The reversal of 100721872 is 278127001.

It can be written as a sum of positive squares in 6 ways, for example, as 22505536 + 78216336 = 4744^2 + 8844^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 100721872.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100721879) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 891288 + ... + 891400.

It is an arithmetic number, because the mean of its divisors is an integer number (3594357).

Almost surely, 2^100721872 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 100721872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107830710).

100721872 is an abundant number, since it is smaller than the sum of its proper divisors (114939548).

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

100721872 is a wasteful number, since it uses less digits than its factorization.

100721872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 100721872 is about 10036.0286966509. The cubic root of 100721872 is about 465.2730842833.

Adding to 100721872 its reverse (278127001), we get a palindrome (378848873).

The spelling of 100721872 in words is "one hundred million, seven hundred twenty-one thousand, eight hundred seventy-two".