1213112231 has 4 divisors (see below), whose sum is σ = 1284471792. Its totient is φ = 1141752672.

The previous prime is 1213112221. The next prime is 1213112233. The reversal of 1213112231 is 1322113121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1213112231 is a prime.

It is a super-2 number, since 2×1213112231² = 2943282570003594722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 71359543 = 1213112231 / (1 + 2 + 1 + 3 + 1 + 1 + 2 + 2 + 3 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213112233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35679755 + ... + 35679788.

It is an arithmetic number, because the mean of its divisors is an integer number (321117948).

Almost surely, 2^1213112231 is an apocalyptic number.

1213112231 is a deficient number, since it is larger than the sum of its proper divisors (71359561).

1213112231 is an equidigital number, since it uses as much as digits as its factorization.

1213112231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71359560.

The product of its digits is 72, while the sum is 17.

The square root of 1213112231 is about 34829.7607083368. The cubic root of 1213112231 is about 1066.5150634909.

Adding to 1213112231 its reverse (1322113121), we get a palindrome (2535225352).

The spelling of 1213112231 in words is "one billion, two hundred thirteen million, one hundred twelve thousand, two hundred thirty-one".