1131011221 has 4 divisors (see below), whose sum is σ = 1135094572. Its totient is φ = 1126927872.

The previous prime is 1131011209. The next prime is 1131011239. The reversal of 1131011221 is 1221101311.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 503508721 + 627502500 = 22439^2 + 25050^2 .

It is a cyclic number.

It is not a de Polignac number, because 1131011221 - 2²¹ = 1128914069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1131018221) 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, 2041260 + ... + 2041813.

It is an arithmetic number, because the mean of its divisors is an integer number (283773643).

Almost surely, 2^1131011221 is an apocalyptic number.

It is an amenable number.

1131011221 is a deficient number, since it is larger than the sum of its proper divisors (4083351).

1131011221 is an equidigital number, since it uses as much as digits as its factorization.

1131011221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4083350.

The product of its (nonzero) digits is 12, while the sum is 13.

The square root of 1131011221 is about 33630.5102696941. The cubic root of 1131011221 is about 1041.8910432011.

Adding to 1131011221 its reverse (1221101311), we get a palindrome (2352112532).

The spelling of 1131011221 in words is "one billion, one hundred thirty-one million, eleven thousand, two hundred twenty-one".