100821864 has 128 divisors (see below), whose sum is σ = 306633600. Its totient is φ = 27202560.

The previous prime is 100821841. The next prime is 100821869. The reversal of 100821864 is 468128001.

It is not an unprimeable number, because it can be changed into a prime (100821869) 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 31 ways as a sum of consecutive naturals, for example, 99022 + ... + 100034.

It is an arithmetic number, because the mean of its divisors is an integer number (2395575).

Almost surely, 2^100821864 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 100821864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (153316800).

100821864 is an abundant number, since it is smaller than the sum of its proper divisors (205811736).

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

100821864 is a wasteful number, since it uses less digits than its factorization.

100821864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1075 (or 1071 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 100821864 is about 10041.0091126340. The cubic root of 100821864 is about 465.4270005358.

Adding to 100821864 its reverse (468128001), we get a palindrome (568949865).

The spelling of 100821864 in words is "one hundred million, eight hundred twenty-one thousand, eight hundred sixty-four".