100111221 has 40 divisors (see below), whose sum is σ = 171730944. Its totient is φ = 56933280.

The previous prime is 100111189. The next prime is 100111229. The reversal of 100111221 is 122111001.

It is a happy number.

It is not a de Polignac number, because 100111221 - 2⁵ = 100111189 is a prime.

It is a super-2 number, since 2×100111221² = 20044513140221682, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100111229) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 216931 + ... + 217391.

Almost surely, 2^100111221 is an apocalyptic number.

It is an amenable number.

100111221 is a deficient number, since it is larger than the sum of its proper divisors (71619723).

100111221 is an equidigital number, since it uses as much as digits as its factorization.

100111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 863 (or 854 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 100111221 is about 10005.5595045954. The cubic root of 100111221 is about 464.3309003213.

Adding to 100111221 its reverse (122111001), we get a palindrome (222222222).

The spelling of 100111221 in words is "one hundred million, one hundred eleven thousand, two hundred twenty-one".