1231211221 has 8 divisors (see below), whose sum is σ = 1283270144. Its totient is φ = 1179923760.

The previous prime is 1231211207. The next prime is 1231211231. The reversal of 1231211221 is 1221121321.

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 1231211221 - 2¹⁵ = 1231178453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1231211195 and 1231211204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231211231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189606 + ... + 195991.

It is an arithmetic number, because the mean of its divisors is an integer number (160408768).

Almost surely, 2^1231211221 is an apocalyptic number.

It is an amenable number.

1231211221 is a deficient number, since it is larger than the sum of its proper divisors (52058923).

1231211221 is a wasteful number, since it uses less digits than its factorization.

1231211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385731.

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

The square root of 1231211221 is about 35088.6195368242. The cubic root of 1231211221 is about 1071.7928486662.

Adding to 1231211221 its reverse (1221121321), we get a palindrome (2452332542).

The spelling of 1231211221 in words is "one billion, two hundred thirty-one million, two hundred eleven thousand, two hundred twenty-one".