10000111221 has 6 divisors (see below), whose sum is σ = 14444605110. Its totient is φ = 6666740808.

The previous prime is 10000111211. The next prime is 10000111259. The reversal of 10000111221 is 12211100001.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 8557175025 + 1442936196 = 92505^2 + 37986^2 .

It is not a de Polignac number, because 10000111221 - 2⁶ = 10000111157 is a prime.

It is a super-2 number, since 2×10000111221² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 1111123469 = 10000111221 / (1 + 0 + 0 + 0 + 0 + 1 + 1 + 1 + 2 + 2 + 1).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10000111211) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 555561726 + ... + 555561743.

It is an arithmetic number, because the mean of its divisors is an integer number (2407434185).

Almost surely, 2^10000111221 is an apocalyptic number.

It is an amenable number.

10000111221 is a deficient number, since it is larger than the sum of its proper divisors (4444493889).

10000111221 is a wasteful number, since it uses less digits than its factorization.

10000111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111123475 (or 1111123472 counting only the distinct ones).

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

Adding to 10000111221 its reverse (12211100001), we get a palindrome (22211211222).

The spelling of 10000111221 in words is "ten billion, one hundred eleven thousand, two hundred twenty-one".