100021221 has 12 divisors (see below), whose sum is σ = 149136000. Its totient is φ = 64529640.

The previous prime is 100021199. The next prime is 100021223. The reversal of 100021221 is 122120001.

It is not a de Polignac number, because 100021221 - 2⁶ = 100021157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100021223) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 178971 + ... + 179528.

It is an arithmetic number, because the mean of its divisors is an integer number (12428000).

Almost surely, 2^100021221 is an apocalyptic number.

It is an amenable number.

100021221 is a deficient number, since it is larger than the sum of its proper divisors (49114779).

100021221 is a wasteful number, since it uses less digits than its factorization.

100021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358536 (or 358533 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 100021221 is about 10001.0609937146. The cubic root of 100021221 is about 464.1917140913.

Adding to 100021221 its reverse (122120001), we get a palindrome (222141222).

The spelling of 100021221 in words is "one hundred million, twenty-one thousand, two hundred twenty-one".