1231222511 has 4 divisors (see below), whose sum is σ = 1233586224. Its totient is φ = 1228858800.

The previous prime is 1231222507. The next prime is 1231222513. The reversal of 1231222511 is 1152221321.

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 1231222511 - 2² = 1231222507 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 (1231222513) 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 3 ways as a sum of consecutive naturals, for example, 1181075 + ... + 1182116.

It is an arithmetic number, because the mean of its divisors is an integer number (308396556).

Almost surely, 2^1231222511 is an apocalyptic number.

1231222511 is a deficient number, since it is larger than the sum of its proper divisors (2363713).

1231222511 is an equidigital number, since it uses as much as digits as its factorization.

1231222511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2363712.

The product of its digits is 240, while the sum is 20.

The square root of 1231222511 is about 35088.7804148278. The cubic root of 1231222511 is about 1071.7961247096.

Adding to 1231222511 its reverse (1152221321), we get a palindrome (2383443832).

The spelling of 1231222511 in words is "one billion, two hundred thirty-one million, two hundred twenty-two thousand, five hundred eleven".