1231221331 has 4 divisors (see below), whose sum is σ = 1233211000. Its totient is φ = 1229231664.

The previous prime is 1231221317. The next prime is 1231221359. The reversal of 1231221331 is 1331221321.

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 1231221331 - 2⁹ = 1231220819 is a prime.

It is a super-2 number, since 2×1231221331² = 3031811931818823122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1231221299 and 1231221308.

It is not an unprimeable number, because it can be changed into a prime (1231221391) 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, 993906 + ... + 995143.

It is an arithmetic number, because the mean of its divisors is an integer number (308302750).

Almost surely, 2^1231221331 is an apocalyptic number.

1231221331 is a deficient number, since it is larger than the sum of its proper divisors (1989669).

1231221331 is an equidigital number, since it uses as much as digits as its factorization.

1231221331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1989668.

The product of its digits is 216, while the sum is 19.

The square root of 1231221331 is about 35088.7636003322. The cubic root of 1231221331 is about 1071.7957823075.

Adding to 1231221331 its reverse (1331221321), we get a palindrome (2562442652).

The spelling of 1231221331 in words is "one billion, two hundred thirty-one million, two hundred twenty-one thousand, three hundred thirty-one".