1001111121 has 18 divisors (see below), whose sum is σ = 1526167890. Its totient is φ = 632278656.

The previous prime is 1001111107. The next prime is 1001111141. The reversal of 1001111121 is 1211111001.

It can be written as a sum of positive squares in only one way, i.e., 929945025 + 71166096 = 30495^2 + 8436^2 .

It is not a de Polignac number, because 1001111121 - 2¹⁴ = 1001094737 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (1001111141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 150816 + ... + 157313.

It is an arithmetic number, because the mean of its divisors is an integer number (84787105).

Almost surely, 2^1001111121 is an apocalyptic number.

It is an amenable number.

1001111121 is a deficient number, since it is larger than the sum of its proper divisors (525056769).

1001111121 is a wasteful number, since it uses less digits than its factorization.

1001111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 308173 (or 308151 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

The square root of 1001111121 is about 31640.3400898284. The cubic root of 1001111121 is about 1000.3702365746.

Adding to 1001111121 its reverse (1211111001), we get a palindrome (2212222122).

The spelling of 1001111121 in words is "one billion, one million, one hundred eleven thousand, one hundred twenty-one".