100206821 has 16 divisors (see below), whose sum is σ = 118540800. Its totient is φ = 83507520.

The previous prime is 100206811. The next prime is 100206833. The reversal of 100206821 is 128602001.

It is a cyclic number.

It is not a de Polignac number, because 100206821 - 2¹⁰ = 100205797 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 100206793 and 100206802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100206811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18956 + ... + 23658.

It is an arithmetic number, because the mean of its divisors is an integer number (7408800).

Almost surely, 2^100206821 is an apocalyptic number.

100206821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

100206821 is a deficient number, since it is larger than the sum of its proper divisors (18333979).

100206821 is a wasteful number, since it uses less digits than its factorization.

100206821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4876.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 100206821 is about 10010.3357086563. The cubic root of 100206821 is about 464.4786556918.

Adding to 100206821 its reverse (128602001), we get a palindrome (228808822).

The spelling of 100206821 in words is "one hundred million, two hundred six thousand, eight hundred twenty-one".