1131212221 has 8 divisors (see below), whose sum is σ = 1143430200. Its totient is φ = 1119014400.

The previous prime is 1131212191. The next prime is 1131212237. The reversal of 1131212221 is 1222121311.

It can be written as a sum of positive squares in 4 ways, for example, as 884408121 + 246804100 = 29739^2 + 15710^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1131212221 - 2⁵ = 1131212189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1131212195 and 1131212204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1131212821) 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 7 ways as a sum of consecutive naturals, for example, 125845 + ... + 134533.

It is an arithmetic number, because the mean of its divisors is an integer number (142928775).

Almost surely, 2^1131212221 is an apocalyptic number.

It is an amenable number.

1131212221 is a deficient number, since it is larger than the sum of its proper divisors (12217979).

1131212221 is a wasteful number, since it uses less digits than its factorization.

1131212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10079.

The product of its digits is 48, while the sum is 16.

The square root of 1131212221 is about 33633.4984948043. The cubic root of 1131212221 is about 1041.9527601529.

Adding to 1131212221 its reverse (1222121311), we get a palindrome (2353333532).

The spelling of 1131212221 in words is "one billion, one hundred thirty-one million, two hundred twelve thousand, two hundred twenty-one".