1111111001221 has 6 divisors (see below), whose sum is σ = 1203155699730. Its totient is φ = 1025640924048.

The previous prime is 1111111001207. The next prime is 1111111001227. The reversal of 1111111001221 is 1221001111111.

It can be written as a sum of positive squares in 3 ways, for example, as 81160032996 + 1029950968225 = 284886^2 + 1014865^2 .

It is not a de Polignac number, because 1111111001221 - 2³³ = 1102521066629 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1111111001227) 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, 3287310486 + ... + 3287310823.

It is an arithmetic number, because the mean of its divisors is an integer number (200525949955).

Almost surely, 2^{1111111001221} is an apocalyptic number.

It is an amenable number.

1111111001221 is a deficient number, since it is larger than the sum of its proper divisors (92044698509).

1111111001221 is an equidigital number, since it uses as much as digits as its factorization.

1111111001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6574621335 (or 6574621322 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 13.

Adding to 1111111001221 its reverse (1221001111111), we get a palindrome (2332112112332).

The spelling of 1111111001221 in words is "one trillion, one hundred eleven billion, one hundred eleven million, one thousand, two hundred twenty-one".