100821680 has 40 divisors (see below), whose sum is σ = 235391184. Its totient is φ = 40160000.

The previous prime is 100821671. The next prime is 100821683. The reversal of 100821680 is 86128001.

It is a Cunningham number, because it is equal to 10041²-1.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×100821680² = 20330022316044800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (100821683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17570 + ... + 22590.

Almost surely, 2^100821680 is an apocalyptic number.

100821680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

100821680 is an abundant number, since it is smaller than the sum of its proper divisors (134569504).

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

100821680 is a wasteful number, since it uses less digits than its factorization.

100821680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5285 (or 5279 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 100821680 is about 10040.9999502042. Note that the first 4 decimals coincide. The cubic root of 100821680 is about 465.4267174007.

Adding to 100821680 its reverse (86128001), we get a palindrome (186949681).

The spelling of 100821680 in words is "one hundred million, eight hundred twenty-one thousand, six hundred eighty".