1231211165 has 8 divisors (see below), whose sum is σ = 1478242008. Its totient is φ = 984443200.

The previous prime is 1231211161. The next prime is 1231211171. The reversal of 1231211165 is 5611121321.

It can be written as a sum of positive squares in 4 ways, for example, as 157076089 + 1074135076 = 12533^2 + 32774^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1231211165 - 2² = 1231211161 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1231211165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231211161) 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, 55262 + ... + 74271.

It is an arithmetic number, because the mean of its divisors is an integer number (184780251).

Almost surely, 2^1231211165 is an apocalyptic number.

It is an amenable number.

1231211165 is a deficient number, since it is larger than the sum of its proper divisors (247030843).

1231211165 is a wasteful number, since it uses less digits than its factorization.

1231211165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131439.

The product of its digits is 360, while the sum is 23.

The square root of 1231211165 is about 35088.6187388447. The cubic root of 1231211165 is about 1071.7928324165.

Adding to 1231211165 its reverse (5611121321), we get a palindrome (6842332486).

The spelling of 1231211165 in words is "one billion, two hundred thirty-one million, two hundred eleven thousand, one hundred sixty-five".