100021205 has 8 divisors (see below), whose sum is σ = 120099672. Its totient is φ = 79967488.

The previous prime is 100021199. The next prime is 100021223. The reversal of 100021205 is 502120001.

It can be written as a sum of positive squares in 4 ways, for example, as 48080356 + 51940849 = 6934^2 + 7207^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100021205 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4337 + ... + 14793.

It is an arithmetic number, because the mean of its divisors is an integer number (15012459).

Almost surely, 2^100021205 is an apocalyptic number.

It is an amenable number.

100021205 is a deficient number, since it is larger than the sum of its proper divisors (20078467).

100021205 is a wasteful number, since it uses less digits than its factorization.

100021205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12375.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 100021205 is about 10001.0601937995. The cubic root of 100021205 is about 464.1916893396.

Adding to 100021205 its reverse (502120001), we get a palindrome (602141206).

The spelling of 100021205 in words is "one hundred million, twenty-one thousand, two hundred five".