1001221111 has 4 divisors (see below), whose sum is σ = 1092241224. Its totient is φ = 910201000.

The previous prime is 1001221097. The next prime is 1001221127. The reversal of 1001221111 is 1111221001.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1001221111 - 2²⁹ = 464350199 is a prime.

It is a super-2 number, since 2×1001221111² = 2004887426224148642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001221811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45510040 + ... + 45510061.

It is an arithmetic number, because the mean of its divisors is an integer number (273060306).

Almost surely, 2^1001221111 is an apocalyptic number.

1001221111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1001221111 is a deficient number, since it is larger than the sum of its proper divisors (91020113).

1001221111 is an equidigital number, since it uses as much as digits as its factorization.

1001221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91020112.

The product of its (nonzero) digits is 4, while the sum is 10.

The square root of 1001221111 is about 31642.0781713212. The cubic root of 1001221111 is about 1000.4068714332.

Adding to 1001221111 its reverse (1111221001), we get a palindrome (2112442112).

The spelling of 1001221111 in words is "one billion, one million, two hundred twenty-one thousand, one hundred eleven".