1211221231 has 4 divisors (see below), whose sum is σ = 1321332264. Its totient is φ = 1101110200.

The previous prime is 1211221213. The next prime is 1211221237. The reversal of 1211221231 is 1321221121.

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 1211221231 - 2⁵ = 1211221199 is a prime.

It is a super-2 number, since 2×1211221231² = 2934113740850310722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211221237) 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, 55055500 + ... + 55055521.

It is an arithmetic number, because the mean of its divisors is an integer number (330333066).

Almost surely, 2^1211221231 is an apocalyptic number.

1211221231 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1211221231 is a deficient number, since it is larger than the sum of its proper divisors (110111033).

1211221231 is a wasteful number, since it uses less digits than its factorization.

1211221231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110111032.

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

The square root of 1211221231 is about 34802.6037962679. The cubic root of 1211221231 is about 1065.9606138801.

Adding to 1211221231 its reverse (1321221121), we get a palindrome (2532442352).

The spelling of 1211221231 in words is "one billion, two hundred eleven million, two hundred twenty-one thousand, two hundred thirty-one".